We have grown Ageratum houstonianum, the Mexican Paintbrush, for a number of years now. Originally we knew Ageratum as one of those short carpet bedding plants that you would see alongside red salvias and orange marigolds in council bedding schemes in the local park.
Some ten years ago we started up Honey Pot Flowers and were trying out new varieties to grow and include in our summer bouquets of British country flowers. We were introduced to the F1 variety ‘Blue Horizon’ which produces flowers on much longer, robust stems and holds extremely well as a cut flower. We have been growing it ever since.
This variety of Ageratum has large, dense flower heads of powder blue. It is not a colour that you find very often in the garden and so makes an interesting addition to both the flower borders and cut flower arrangements. Most importantly, once established it does seem to be a very well behaved plant, growing and flowering reliably throughout the summer.
It is a native of Central America and Mexico and it is worth noting that in some countries it is considered an invasive weed. We have certainly not found this to be a problem here in the UK climate.
I have just sown this year’s seeds (14th February). The tiny seeds are surface sown on a half tray of pre-watered, well drained multi-purpose compost. To ensure the seedlings do not damp off in their early days we mix the compost with a generous amount of perlite. I like to water the compost before sowing so that the tiny seeds do not get washed into the corner.
The half tray is covered with cling film to remove the need for any extra watering before the seedlings emerge. They will sit on a warmish kitchen windowsill now for a few weeks until the green shoots appear at which point we will slowly loosen the cover and acclimatise the small plants before removing the cling film altogether.
Looking at previous years’ records I will be pricking these out into larger trays in about five weeks time (towards the end of March), and will have planted them out into the garden by 6th May. They are not frost hardy so this would need to be adjusted to suit your own circumstances.
Our past records also indicate that we have been picking Ageratum for cutting by mid-June and they then continue to flower right through to the first frosts in the Autumn.
Over the years we have tried them in various parts of the garden but they do seem to grow best in full sun in soil that remains moist all the summer. Our garden soil can dry out rapidly in the height of the summer but there are areas in part shade that retain some moisture in the soil. The Ageratum also seem to thrive in these areas.
What we particularly like about Ageratum is how trouble free it is. It does not seem to be attacked by pests which is ideal if you want to grow good quality, clean stems for cutting, arranging and/or selling. In researching the plant this year I was surprised to find that it has its own secret defence mechanisms when it comes to fending off insects.
Ageratum has evolved a method of protecting itself from insects by producing a compound that interferes with the insect organ responsible for secreting juvenile hormone during growth and development. The chemical triggers the next moulting cycle prematurely and renders most insects sterile. Fascinating stuff!
We have been experimenting this year by creating a range of different summer planters to add pops of vibrant colour throughout the garden. Next year is our daughter’s wedding which we are hosting here in the garden and it is giving us a chance to see just what works and what is less successful. It is still early days but here are six that look particularly promising so far.
One: Surfinia Pink Vein
These pink surfinias, grown from plugs, are stunning little plants producing huge numbers of these striking flowers. We have planted them in a large terracota planter surrounding a central pink leaved cordyline and partnered with grey leaved Helichrysum petiolare, purple verbena and white bacopa.
Two: Begonia odorata ‘Angelique’ and Begonia ‘Cascading splendide ballerina’
In previous years we have found that these large begonias make a real statement on the patio. We normally grow the lighter ‘Angelique’ but this year have partnered it with the orange ‘Ballerina’. Looked after carefully over winter the corms will grow larger and larger every year so an initial investment can provide years of pleasure. I think these sit nicely with the lavender and wisteria.
Three: Super Petunia (Beautical) – French Vanilla, Caramel Yellow and Cinnamon
Super Petunias are calibrachoa and petunia hybrids. So far they are performing extremely well and it will be interesting to see if we can keep them looking fresh and wonderful throughout the summer months.
Four: Lotus Fire Vine
We have also been looking for something that will trail nicely from hanging baskets and provide a more tropical look. These Lotus Fire Vine plants have been slow to get going but they are now coming into flower producing these interesting claw-like orange flowers which look lovely against the glaucus foliage.
Five: Super Petunia (Beautical) – Bordeaux and Sunray Pink
Here we have some more Super Petunias this time in pink and a deep, dark velvety burgundy. They look great contrasting against the dark Cotinus and the silver foliage of the Santolina.
Six: Zaluzianskya (Nigh Phlox)
Finally for something completely different. As the wedding is in August next year we are of course hoping for a warm, sultry summer evening where the guests can wander amongst the plants and enjoy a garden at dusk filled with scent. Zaluzianskya is certainly not a large plant but these tiny flowers fill the air with a wonderful fragrance.
Individually the delicate, tissue paper like flowers of the Poppy may be quite fleeting in nature but on mass they can provide a beautiful and vibrant show over many weeks. In a meadow style planting they also provide that much needed movement as they gently sway in the summer breeze.
The Poppy family (Papaveraceae) offers the gardener a range of annual, biennial and perennial species in an amazing spectrum of colours that span yellow, pink, scarlet, deep plum, orange, blue and white. Certainly not all poppies are red!
Papaver rhoeas (Common Poppy)
Despite the adoption of modern agricultural practices and the reduction of our native poppies in the countryside we do still see the occasional field full of red poppies as we drive across the Cotswolds in summer.
Probably more common in the garden setting are Shirley poppies. These were initially bred from field poppies by the Rev. William Wilks, vicar of Shirley in Surrey in the late 1800’s. He selected a range of white edged flowers that have now been developed into a range of tones.
Papaver rhoeas is an annual herbaceous plant usually flowering in late spring and into summer.
Papaver nudicaule (Iceland Poppy)
Another common garden plant is the Iceland Poppy. It originates from sub-arctic regions and can grow to a height of 1-2½ feet. It is the poppy most frequently grown as a cut flower and is also a charming garden plant.
P. nudicaule (nudicaule meaning bare stemmed) is a perennial that is most commonly grown from seed as an annual. Sown at 18-24º C the tiny seeds will germinate in 7-12 days. These seedlings can be pricked out into modules to grow on and then be planted out when conditions are suitable.
Interestingly Iceland Poppies do poorly when the temperature rises above 21º C. The plants flower from mid-spring to mid-summer and usually produce 10-15 stems before being checked by warmer temperatures.
Papaver somniferum (Opium Poppy)
The Opium Poppy is an attractive, upright annual herbaceous plant that can grow to a height of around 100cm. As a garden plant they have been bred in a number of colours in both single and double forms although we have found the double forms are sometimes too heavy to stand upright on their stems. The foliage has a characteristic blue-green glaucous apprearance and they seed themselves freely around our garden.
The seed heads are particularly attractive and can be used both green and dried in flower arrangements and wedding buttonholes.
Papaver orientale (Oriental Poppy)
The Oriental Poppy is a very hardy perennial poppy growing to a height of 3 feet with a spread of 2 feet. For us it is a very reliable spring flowering herbaceous plant that produces a large number of large, hand-sized flowers. The large fleshy stems and foliage will often need staking to keep them looking at their best.
They originate from the Caucasus, north eastern Turkey, and northern Iran and in the wild grow on rocky slopes and dry meadows. Originally orange these plants now have cultivars that come in a wide range of colours. We have found the white varieties are particularly prone to damage if we get a lot of rain and can look like a sad, soggy hankerchief at times.
Oriental poppies combine well with other plants in low herbaceous borders. One of my favourite parts of the garden combines these pink oriental poppies with aquilegia, ox-eye daisies, purple flag iris, lime-green alchemilla and dusky pink valerian.
It is worth mentioning that by mid-summer the foliage and flowers of P. orientale will have died down entirely and will need to be cut back. To continue the display into late summer it is important to surround these poppies with other later flowering perennials.
Eschscholzia (Californian Poppy)
Grown well Californian poppies can produce a spectacular show of delicate, bright orange blooms complemented by equisite blue green foliage. Ever since seeing the wonderful display at East Rustan Old Vicarage in Norfolk I have been trying to grow these in our own garden – but with only limited success. Native to California, these hardy annuals grow in dunes, rocky hills and roadside banks and I can only think that our soil and conditions here in the UK Midlands are a little too damp to allow them to thrive.
Meconopsis betonicifolia (Himalayan Poppy)
We have found the beautiful blue Himalayan Poppy to be somewhat of a challenge to grow successfully. It is something that Carol’s grandfather, Fred Mason, grew successfully in his garden in Bolney in Sussex for years. Although we have tried on a number of occasions we have never managed to keep this perennial poppy going from year to year.
Its delicate, true blue petals are truely enchanting and a definite showpiece when you are successful however.
As the name suggests blue Meconopsis are native to the Himalaya and Western China. They grow in alpine meadows, woodlands and on screes and like cool, damp summers. Although we have cool and damp winters our summers here are increasingly hot and dry and our clay soil holds little moisture in the heat of the summer. The reference books indicate that Meconopsis need plenty of water in summer and as little as possible in winter which does not sit at all well with our conditions. However, there are plenty of other Poppies that we can grow very successfully.
Meconopsis cambrica (Welsh Poppy)
To illustrate the point above a related Meconopsis, the yellow Welsh Poppy, grows very successfully here at Waverley. It is the only Meconopsis that is native to western europe. It is a short -lived, delicate perennial that seeds itself freely.
In general poppies are easy to grow and like sun or semi-shade in moist but well drained soil. I think they look at their best if planted in generous clumps.
The annual species ( such as P. rhoeas ) do not like to be transplanted and so are best sown where they are to flower. It is important not to cover the tiny seed as they need light to germinate. As cornfield plants they are naturally colonisers of disturbed ground and the seeds can survive in a dormant state for many years before being exposed by ploughing. They will then germinate rapidly if conditions are right. This is also the reason why they are associated with battlefields where the ground was distrurbed by the bombs, grenades and troop movements.
Biennials or short lived perenial species (such as P. nudicaule) are more tolerant of being transplanted. We sow these on the surface of trays of multi-purpose compost (again not covering the seed) in an unheated greenhouse. When the plants are big enough to be pricked out we plant them up into larger modules and allow them to grow on. The modules are them transplanted out when conditions are right trying not to disturb the roots if at all possible.
The larger perennial species (such as P. orientale) are best propagated by root cuttings in the winter especially if you wish to retain the characteristics of a particular cultivar. They are unlikely to come true from seed.
Many poppies will self seed freely if the conditions are right. We have not found them to be at all invasive and if they do happen to seed themselves somewhere they are not wanted they are very easy to remove.
Cutting and conditioning
It is possible to use poppies as cut flowers but they do need to be cut at the right stage, prepared and conditioned appropriately to get the best out of them. We do not find them particularly long lasting but they do certainly add a definite country feel to any bouquet.
Poppies for the vase should be cut when the flower buds are beginning to break and the colour is just able to be seen. If they are fully open they will be difficult to condition.
The base of the stems should be seared in boiling water for 20-30 seconds before topping up the vessel with cold water. The stems should then be left to condition in a cool place, out of direct sunlight for at least 2 hours and preferably overnight. The searing process reduces the flow of the milky sap (latex) which would otherwise bleed out and clog up the xylem vessels which transport the water up to the flower.
It is worth highlighting that many types of poppy produce interesting seed heads that are also excellent for autumn and winter arrangements (along with the seed heads of nigella, teasel, honesty and dried hydrangea flowers).
In our ceramics we have also found that poppy seed heads can be used to make some interesting botantical texture effects that will be picked out by using oxides or suitable glazes.
“Specialty Cut Flowers” by Armitage and Laushman (ISBN 0-88192-579-9)
“The Cutting Garden” by Sarah Raven (ISBN 978-0-7112-3465-9)
“The Flower Farmers Year” by Georgie Newberry (ISBN 9780857842336)
“100 flowers and how they got their names” by Diana Wells (ISBN 1-56512-138-4)
“A-Z of perennials” Consulting Editor: Lizzie Boyd (ISBN 0-276-42087-X)
“A-Z of annuals, biennials and bulbs” Consulting Editor: Lizzie Boyd (ISBN 0-276-42089-6)
“Perennial Volume 2: Late Perennials” by Roger Phillips and Martyn Rix (ISBN 0 330 30936 9)
One of the best things to do on a cold, wet December day is to think back to those sunny days in the summer and reflect on what worked well in the garden. Sometimes it is a vista or combination of plants that have matured gracefully and now perform well year after year. At other times it is just a moment when some of the short lived annuals all come together and you stand and look and admire. Within a couple of weeks the garden will have moved on.
In one quadrant of the new flower garden this year we allowed a number of self sown annuals to develop whilst some of the new perennials were being planted and growing on. The annuals included Love-in-the-mist (both the blues of Nigella damascena and the white Nigella hispanica ‘African bride’), Corncockle (Agrostemma githago) and some beautiful mixed colour pink poppies with their thin tissue paper petals (Papaver rhoeas ‘Falling in Love’). This informal combination grew freely amongst the tall biennial Sweet William (Dianthus barbatus ‘Auricular Eyed’).
The effect was charming and created a relaxed ‘meadow-style’ bed. Along with the mass of different colours and the texture of the fresh green foliage the bed also had movement. The different components swayed and reacted to the breeze adding an additional dimension.
All of these annuals cut well and, if appropriately conditioned, allow you to enjoy these flowers for many days in a vase indoors.
The pictures here were all taken in the first week of June. It was a sweet spot when all the flowers were emerging together and in their prime. As well as the overall effect I also like to look at the detail of the individual flowers. The tiny, delicate rows of fine dots in the Corncockle and the blue wash in the centre of the Nigella hispanica are particularly lovely.
At its peak this meadow style planting was certainly a triumph. However, I think it is worth highlighting that it is relatively short lived. This is certainly a downside in a garden where you want to try and create year-round interest. Once they have set seed the show is over and you do need to have something planted that will follow on. If you want a show next year you do of course have to leave the seed heads to mature and set seed. The Nigella seed heads look particularly striking and are well worth leaving to add interest to the late summer border.
My conclusion therefore is that whilst self sown annuals do indeed provide a spectacular show, in a garden setting you do need to set them amongst other follow-on perennials or small shrubs that can continue the performance into July, August and the autumn.
This week’s Six on Saturday highlights six very different plants that have caught my attention this week as I have worked in the garden. A few showers of rain have brought the garden to life without damaging the blooms.
This is a first for us this year. It has a tiny flower, perhaps not much bigger than your thumbnail, but in only a few short weeks it has grown up from seed (sown on 25th March) and is already flowering profusely. We have included this in our patio pots and it seems to be settling in nicely. As well as being a charming little flower it is the movement of the stems in the gentle breeze which adds to its character.
We have a range of lupins across the garden but this one (name unknown) is particularly striking in the old rose garden. It is a scrumptious colour and goes so beautifully with the foxgloves.
Three: Nigella damascena (Love-in-a-mist)
We have grown Nigella damascena and Nigella hispanica for a number of years to include in our country flower bouquets. It has now seeded itself across much of the flower garden and we are happy to allow it to develop amongst more established plants. It is very easy to weed out if we have too much of it growing in the wrong place. Both the flowers and the resulting seed heads make excellent additions to any bouquet.
We have also seen a significant increase in goldfinches in the garden in recent years. Whether this is a result of the increased availability of niger seeds who knows but it is a happy coincidence.
Four: Aquilegia ‘Blue Star’
As with Nigella, we love to let the Aquilegias seed themselves throughout the cottage garden. They are definitely an important part of our spring garden but they do tend to be consistently in the pink/purple ‘granny’s bonnet’ range.
To introduce a slightly different form and colour range we sowed Aquilegia ‘Blue Star’ seeds last year and put the plants out last autumn. These have established well and are now producing these lovely delicate flowers. For some reason these choicer varieties have tended to be short lived perennials and have not always lasted very long in the garden.
Five: Clematis ‘Voluceau’
Over nearly 25 years we have planted a large number of different clematis throughout the garden. Some have absolutely romped away whilst others have only had very limited vigour.
I don’t recall seeing this Clematis ‘Voluceau’ for many years but Carol assures me it has been there all along. This year it has sprung into life. It was probably planted over 15 years ago and has gently chugged way over the years without any great show. It may be that we have recently cleared, improved and fed the rather tired bed that it sits in. I am not sure the picture really shows off the real-life velvety plum purple of this variety. It has a really rich colour.
Another favourite from our commercial flower growing days. These intricate, pin-cushion, rose coloured flowers are always a joy. They seem to like our soil and come back reliably year after year as long as you keep the weeds at bay.
Campanulas are without doubt one of the most charming of cottage garden plants. The taller species typically grown in gardens provide heads of loose open bell-like flowers in blue, white, purple and sometimes pink. Some however have a low creeping habit and are very at home around the edge of a patio or tumbling over stones in a rockery.
There are over 500 species in the genera Campanula¹ and so it is going to be difficult to do the genus justice. I will concentrate here on those that we grow in the gardens at Waverley or have used as cut flowers over the years (C. medium, C. persicifolia, C. latifolia, C. glomerata, C. pyramidalis and C. portenschlagiana).
Campanulas mainly come from the temperate and sub-tropical regions of the northern hemisphere. Many are native to Europe originating in the Mediterranean and eastwards to the Caucasus mountains. Understanding where these plants come from and the conditions they enjoy in the wild, is critical to providing them with the conditions in which they will thrive in your own garden.
Some species of Campanula are annuals, whilst others are biennials or perennials. Although species like C. medium may be perennial in some areas we tend to grow them as biennials so that we get fresh vigorous flowering plants each year.
Sowing from seed is very straight forward. The seeds are very small and typically we would sow thinly onto the surface of moist compost in the spring and then cover the tray with cling film until the seeds germinate. I usually remove the cling film as soon as the green shoots emerge to avoid any danger of damping off. Try to avoid watering from the top as the seeds will easily be washed into the corner of your tray.
Once the seedlings have their first true leaves they can be pricked out into larger trays or modules and grown on. They seem to transplant very successfully. As we grow species like C. medium as biennials we prick them out into large modules where they stay until mid-September. At this point the established plants are very easy to set out in groups around the garden where they over winter and flower in early summer.
The hardy perennial species eg. C. persicifolia are perhaps easier to propagate by division every few years. I simply dig up a clump, separate out the new rosettes and pot them up into individual 9cm pots filled with a mix of perlite and multi-purpose compost.
All of our Campanulas do well throughout the garden when planted in full sun or partial shade. As tall plants C. medium look very effective peeking out behind our low formal Lonicera nitida hedges and in front of the more informal woodland edge of the garden boundary . Many writers recommend that they prefer a moist but well drained soil.
Pest and diseases
I have to say that we find all our Campanulas to be pretty resilient to pest and diseases. It is reported that they are susceptible to slugs and snails but we have very little problem (perhaps they are attracted away by other more tasty morsels!).
It is also reported that they are prone to powdery mildew and rust diseases but again we have had little problem with these diseases on our plants. In order to see the flowers at their best we do space the plants well apart and this may well allow plenty of air to circulate between them thus keeping these diseases at bay.
Armitage and Laushman² report that Campanulas do not seem to need a period of cold treatment to start producing rosette leaves but do need a period of cold to initiate flowering. C. persicifolia, for example, requires 12 weeks at or below 4°C to initiate flowering. Treating sown plants as biennials seems to sit well with these findings. Our spring sown plants of C. medium do not seem to flower in the year that they are sow. However, planted out in mid-September and allowed to over winter in the cold flower beds they produce robust, upright, tall plants that flower over a long period.
Armitage and Laushman also indicate that C. persicifolia is day neutral which means it flowers under both short or long days once the cold treatment requirements have been satisfied. For other Campanula species long days are required for flowering after vernalisation. (see: How plants use day length to decide when to flower (Photoperiodism) for more background on this).
It would appear that the new Champion series of Campanula medium does not require cold treatment which means they can be grown more effectively in greenhouse conditions. This helps enormously if you are growing purely to produce cut flowers and want a longer season of production.
Cutting and conditioning
It is certainly our experience that the tall varieties of Campanula all make excellent cut flowers. The inflorescence opens from the bottom providing a long period of interest in the vase and in the garden.
Typically you would cut when the bottom one or two flowers have coloured and are open. We use a standard conditioning approach of cutting the flowers directly into cool, clean water containing ‘flower food’ to keep the water fresh and minimise bacterial development.
The stems often produce sap when cut so it is wise to keep them in a separate bucket from other flowers, rinsing the cut stems every 20 minutes or so until the sap stops flowing.
C. medium, C. persicifolia, C. latifolia and C. pyramidalis all offer a light, airy and open effect which is ideal for natural, country style arrangements and bouquets. C. glomerata is perhaps more structural, upright and dense in form but its strong purple shade works well with bold colours like oranges and scarlets.
Whereas many of the Campanulas we grow are upright and need some support to produce quality blooms we have seen beautiful trailing forms on our travels in Croatia and Montenegro this year growing in very dry, well drained, rocky conditions on walls and buildings. It is often very difficult to get good trailing colour for use in flower arrangements and this growing approach is well worth considering.
Campanula medium (Canterbury Bells)
Originating from southern Europe¹ these large robust plants grow to 2 feet to 2 feet 6 inches in height. They have a long flowering season starting in June and continue through to August. As the flowers open consecutively from the bottom to the top they provide a long period of interest and colour. They are quite heavy plants and although they have robust stems they do tend to need some support to stop them looking untidy.
We grown these from seed each year and treat them as biennials. The RHS considers them to have a hardiness rating of H4 (Hardy through most of the UK (-10 to -5)).
We have grown two forms: the cup and saucer varieties which have big robust flowers on strong stems and also the singles (which do not have the saucers). We do find these rather ‘chunky’ in nature and are not really delicate enough for use in bouquets and small arrangements.
The ‘Champion’ series, however, that you typically get from your floristry wholesaler are a very different cut flower and we have used these extensively over the years. Grown as an annual they can be brought through to flowering in around 15 weeks. They are available in a range of colours from blue through white and to pink.
Campanula persicifolia (the peach leaved campanula)
To my mind C. persicifolia is rather more attractive and delicate than C. medium. This species is a perennial that is native to most of Europe and the Benelux countries eastwards towards Central and Southern Russia and North West Turkey³. It seeds itself freely around our garden but is also easy to multiply by division (the latter technique particularly useful if you want to bulk up the delicate ‘alba’ form).
C. persicifolia has evergreen foliage and has been given the H7 hardiness rating by the RHS (Hardy in the severest European continental climates (< -20)). In nature it grows in meadows, open woods and on the edge of forests.
As with C. medium the inflorescence opens from the bottom to the top. This give a long period of flowering in the garden border. Flowering can be extended still further by dead heading. In this case you are not removing the whole flower spike but removing the individual dead flowers before they set seed. You will find new flowers develop at the base of each flower stem.
Campanula pyramidalis (the Chimney Bell Flower)
When grown well C. pyramidalis can grow up to 2 metres in height producing tall spikes of pyramid shapes flowers that are excellent for large flower arrangements. Flowering from May until July, it is a short-lived perennial that, like C. medium, is often grown as a biennial. It is native to southern Europe and the western Balkans¹.
Campanula glomerata (the clustered bellflower)
C. glomerata is a vigorous rhizomatous perennial that has a tendency to sucker. The species is native to the North Temperate Zone of Eurasia, from Europe to Japan¹. It grows to around 1-2 feet in height producing clusters of typically deep purple flowers on strong stems. There is also a beautiful crisp white variety (see below). The RHS website indicates that it is hardy in the severest European continental climates (< -20) (RHS hardiness rating H7).
Campanula latifolia (the giant bellflower)
Very much more delicate than C. glomerata or C. medium, C. latifolia is one of my favourite Campanulas in the garden. It seeds freely and seems to come back without problems year after year in a rather inhospitable spot in the garden. We tried to move some seedlings to what we considered to be rather better soil and they just did not ‘do’. The answer I think is that that actually like poor dry soil.
C. latifolia is again native to Europe extending to western Asia as far east as Kashmir.
Campanula portenschlagiana (the wall bellflower)
Very different in form from the others mentioned in this article is C. portenschlagiana. This is a very robust, low growing creeping plant that in our garden grows in minimal soil around the base of the house and patio steps. It was at the house well before we arrived 25 years ago and I am sure will still be about when we finally leave. It produces masses of blue flowers throughout the summer.
It is an alpine plant and requires a very well drained area in full sun to thrive. We have found that is does not compete well with plants like Saxifraga x urbium (London Pride) which can easily swap this Campanula if not kept in check.
And finally some trivia …
Su Whale⁴ in her guide on cut flowers cites the following charming piece of flower trivia. In Germany and in the Netherlands the Campanula flower is known as ‘Rapunzal Bellflower’ and supposedly was the inspiration behind Grimm’s fairy tale.
As we move into September the evenings are drawing in and are already beginning to seem a little cooler although during the day there is still plenty of sunshine and warmth to enjoy.
This new month has seen the beginning of a transition. Some of the summer perennials, shrubs and roses are beginning to put on a new flush of colour whilst others are now beginning to emerge for the first time giving new form, colour and texture to the garden borders.
One: Kniphofia ‘Lord Roberts’
This particular Kniphofia comes into flower in early September and brings a dramatic spark to the yellows, blues and purples of the late summer border close to the house. I am not a fan of all the red-hot poker family but there are some interesting varieties that I feel are worthy garden plants. ‘Lord Roberts’ is certainly one of these although it does need supporting to stop the large heads flopping forward as they come into full bloom.
Two: Gaura lindheimeri
This group of Gaura plants were something that I successfully grew from seed a few years back. They are growing in the cut flower garden and have established into large clumps that create a tremendous show for a long period. They have been in flower now for quite a few weeks but are still going strong in early September. They add a light, airy movement to the flower garden and sit very well with Verbena hastata ‘Blue spires’.
An excellent plant but certainly one that needs support to avoid it flopping over the grass and potentially getting damaged by the mower as I wizz past.
The Dahlias certainly seem to have been late flowering here in the UK Midlands this year and only now at the beginning of September are they beginning to come into full flower. They are usually one of our main cutting flowers at this time of year.
Choosing just one from the many varieties in the garden is difficult but this picture of the variety ‘Dark Spirit’ has come out rather well I think. Of the tubers we dug up last winter ‘Dark Spirit’ proved to be the most resilient and survived the long cold winter much better than many of the other varieties. The Dahlia tubers that survived best were in fact those that were left in the ground and covered with straw.
Four: Hydrangea ‘Lime Light’
Despite the hot dry conditions during mid summer, the hydrangeas seem to have performed surprising well and continue to produce large clean flower heads. This one is ‘Lime Light’ which lives in an area shaded from the midday sun in relatively moist conditions.
We have a number of different Abelia plants around the garden and they really come into their own at this time of year. Unfortunately we have lost the name tags on most.
The Abelia in the garden are all small, tidy and very well behaved shrubs. They take very little looking after and at this time of year are covered in either small pink or white flowers. The bees just love them.
The picture here shows them partnered with Penstemon ‘Garnet’.
Six: Cosmos ‘Lemonade’
The final selection this week is the delicate lemon yellow Cosmos variety ‘Lemonade’. They are much smaller and more delicate than the full-on show created by the pinks and whites of Cosmos ‘Sensation Mix’ but they are so charming and certainly deserve to be grown and appreciated.
Last week’s ‘Six on Saturday’ was a bit challenging as I just couldn’t decide which six to feature! So, this week I have come back with another six stars of the August garden.
One: Dahlia ‘Apricot Desire’
There are so many dahlias to choose from in late summer but this variety, ‘Apricot Desire’, seems to have performed very well this year. It is such a beautiful and well shaped bloom. Generally the dahlias seem to have been later this year but the plants are still looking very good and the buds are forming well.
As the picture shows, it will not be long until the Asters begin to flower as well and we are certainly looking forward with anticipation to the potentially striking combination.
Two: Ageratum ‘Blue Horizon’
We have grown a number of varieties of Ageratum over the years and the F1 ‘Blue Horizon’ stands out as both an excellent cut flower and border plant. It is relatively tall, has strong stems and seems to just flower and flower and flower with little attention. The powder blue is also quite unusual and sits well with yellows, whites and pinks. Ageratum ‘Blue Horizon’ is a plant that we grow without hesitation every year now.
We grew this for the first time last year in large patio tubs and it performed wonderfully (see: Chincherinchee (Ornithogalum thyrsoides) ). We tried to overwinter the bulb with little success as they split into multiple tiny bulbules and presumably will take many years to grow big enough to flower effectively again. As they are so cheap we bought another batch this year, started them in large pots and then planted out into the flower garden.
Once again they have grown into excellent plants and are producing good, strong stems (c. 18 inches) topped with these charming white flowers. What I particularly like is that the don’t need any staking. The second flush of flowers is beginning to develop now and they will probably carry on flowering until the first frosts.
Four: Phlox (probably ‘Bright Eyes’)
The Phlox in our garden never seem to be as big and lush as they are in other peoples’ gardens but they are such a lovely, fragrant flower that we continue to try year after year to develop and improve them. They seem to thrive best in parts of the garden where there is continual moisture in the soil throughout the year. Although we have some wonderful white Phlox in full sun they do need continual water to stop them flopping at the first sign of any drought.
Five: Aster × frikartii ‘Mönch’
Aster ‘Mönch’ comes into flower a few weeks earlier than many of the other ‘September flowers’ (see: Michaelmas daisies in the autumn sunshine ). It is a charming plant with a loose airy habit and makes a wonderful cut flower. It is a perfect flower for many of our country style wedding bouquets.
Six: Rose ‘Prince Jardinier’
This is one of the new roses that we have planted in the redesigned cut flower garden (see: New additions to our garden of Roses ). Many have been repeat flowering but this variety just continues to produce these delicate light blooms with a darker pink centre. Exquisite.
Despite the weeks of dry weather here in the UK Midlands some of the garden plants have still performed wonderfully during August. These late summer flowers are adding a real freshness to the garden which has otherwise looked rather dry and scorched.
Here are my ‘Six on Saturday’ star performers.
One: Agapanthus africanus
These are the large evergreen Agapanthus with strap like leaves. They tend to be more tender than the deciduous types. These plants are growing in large terracotta pots that we take into the greenhouse for protection over the winter months.
Two: Sunflower ‘Vanilla Ice’
This is a medium height sunflower with delicate lemon yellow hand-sized flowers. They do need some support but if you keep dead heading you get a succession of good quality flowers throughout the summer. As you can see they are also enjoyed by the bees.
Three: Physostegia virginiana
This is a perennial that thrives in damp soil and full sun. Part of the cut flower garden is waterlogged for most of the winter and also remains moist through the summer months. The Physostegia (along with the Astilbe) love these conditions.
Four: Cosmos ‘Sensation Mixed’
One of my favourites. It is such a happy looking plant and the large colourful flowers complement the green fluffy foliage wonderfully. Over the years we have learnt not to treat it too kindly. If you plant it in ground that has not been previously cultivated you get masses of green leaves and very few flowers until very late in the year. Not terribly helpful for cutting. Growing in poorer ground with little additional fertiliser gives you many more flowers earlier in the year.
It has been difficult to choose just one Rudbeckia. They are so important to the late summer garden yielding masses of bold yellow and rust coloured flowers. This particular variety is an annual Rudbeckia hirta ‘Autumn Forest’.
Last but certainly not least in this six is the Abyssinian gladiolus, Acidanthera murielae. Unlike many of the garden gladioli it looks delicate and elegant and moves gently in the breeze. It has a wonderful scent and is good for cutting.
One flowering annual that has thoroughly enjoyed the hot weather this year has been the Zinna. Whereas the Dahlias appear to have been delayed this year the Zinnias have produced tall, strong, clean plants with masses of excellent quality flowers.
I must admit that in previous years my Zinnas have struggled and if you get a cool period they just seem to sulk. In order to try and improve their chances in the future, even in cooler years, here are a few things to consider.
Grown from seed Zinnia will germinate in 3-5 days at 27-29°C and 5-7 days at 21-24°C.¹
The seedlings should be grown on with night time temperatures of 15-18°C and day time temperatures of 21°C.¹
Zinnas dislike root disturbance so ideally the seeds should be sown in individual modules to reduce disturbance at the planting out stage.
Plant out at a spacing of around 6 inches apart. The denser the spacing the taller the plants.¹
Zinnas are quantitative short day plants (see How plants use day length to decide when to flower (Photoperiodism) ). This means that they flower more rapidly under short days but eventually flower regardless of photoperiod. Long days (greater than 12 hours) produce longer stems but delay flowering. Similarly if you plant a succession of Zinnas after the longest day they will flower on shorter stems.¹
Benzakein⁴ emphasises the importance of pinching out the central flower bud when the plants are 18 inches tall to encourage the development of lower branches on the plant.
Zinnas do seem to be prone to powdery mildew particularly if growing in conditions where hot days are followed by cool damp nights. Over watering can cause similar problems.
If you are growing for cutting, pick the flowers before the pollen matures. If you can see fluffy, mature pollen the chances are the bees have done their job and the flower is now redundant and will wither to allow the seed to develop.
There seems to be a difference in view as to whether Zinnas like ‘flower food’ or not. Beutler² states very clearly that they do not like floral preservative whilst Benzakein⁴ is an advocate of its use with Zinnas.
Zinnas are long lasting in water but will wilt rapidly out of water and it is reported that they do not work well in corsages and buttonholes.²
In reality there is little that many of us can do about the great British weather and in some years different species will grow better than others. Certainly Zinnas like it hot and starting to grow the seeds too early if you don’t have the facilities to keep them warm can reduce your chances of success.
Keep in mind that Zinnia elegans is a warm-hot climate plant native to Mexico growing in scrub and dry grassland. Not every year will be suitable for them here in the UK but their bright vivid colours in late summer are certainly striking when conditions are right.
Half Hardy Annual
Flowering period: July to October
Latin name:Zinnia elegans (after botanist Johann Gottfried Zinn (1727-1759)) ¹