My garden is so jam-packed with plants by early autumn that I can barely move around outside. Far from holding plants back, a spell of cooler, duller weather has encouraged exuberant growth and the appearance of lashings of fresh foliage. Flowers are in shorter supply, but there are enough to give the garden interest and punctuation. I particularly enjoy September as I can take my foot off the pedal and just let things go. Colocasias and bananas suddenly achieve gigantic proportions, grasses arch across the pathways and fuchsias drip with dancing flowers. It’s a magical month, whilst at the same time signalling the beginning of the end of the gardening year.
My coleus have responded quickly to a fortnight of variable weather, their foliage becoming larger, richer and brighter every day. Despite being considered heat and sun resistant, Solenostemon ‘Henna’ has been revitalised by showers and fresher mornings, the leaves once again a brilliant Chartreuse backed by henna-red. It’s a dazzling combination. During the heat of summer the leaves had turned pale gold in places, giving the plant a sickly appearance. The effect was not unattractive, but I was not enamoured: I much prefer the foliage now it’s back to its brick-and-acid brilliance.
Solenostemon ‘Henna’ is a relatively new coleus, trialled extensively in the USA where coleus are significantly more popular than they are here in the UK. It quickly makes a large plant and propagates easily from cuttings, which can be rooted in a glass of water and then potted on. I am taking a few cuttings every fortnight so that I have plenty of smaller plants to overwinter. The parent plant is now 4ft tall and counting. I’ve already described how the colour and quality of Henna’s foliage is greatly influenced by the amount of sunlight it catches, which is the same for many coleus. Too bright and any variegation changes colour, loses definition or disappears completely. This varies for every variety and some are certainly more tolerant of full sun than others. For me, the value of coleus is that they bring fabulous colour and variety to a partly shaded garden so I am not fussed about growing them in baking sunshine. Healthy coleus cope well with dull, damp weather, although the same conditions appeal to slugs and snails which find them delicious.
What I particularly like about ‘Henna’ is that it’s a bright, robust and vigorous plant that injects unique colours and textures among more conventional foliage plants. The leaves have an almost reptilian surface and jagged edges, reminding us that coleus are often referred to as flame nettles. Looking back I can see how dramatically the degree of serration around the edge of each leaf increases as the plants reach maturity. S. ‘Henna’ is shy to flower. This is a bonus, since flowering in coleus is deemed a negative. Coleus flowers are not interesting and their appearance normally signifies the decline of the plant. It’s best to nip them off if they do start to appear, although this can be a losing battle. I did not have to do anything to encourage a bushy habit, the plant did that for itself. With some coleus it’s beneficial to pinch out the main growing tip to encourage side shoots to form.
If had to identify any drawbacks it would be that ‘Henna’ is a little fragile, both in terms of the strength of the main stems and the tear-resistance of the leaves. I may experience these issues because my garden is very sheltered, causing plants to get a bit ‘soft’, but it’s nothing a few short pea sticks wouldn’t prevent at planting time. ‘Henna’ is also not the easiest plant to place, especially in a garden full of flowers. I think it works best with plainer foliage, whatever the colour, and alongside other coleus.
I know that many visitors marvelled at this unusual coleus when they visited my garden in August and I hope that they will all seek it out. Coleus deserve to be more widely grown, either as houseplants or summer bedding plants. They are easy to grow, almost pest free (darn those slugs and snails!) and as colourful as the most extrovert blooms. ‘Henna’ is one of the biggest and best, so why not give it a try next summer?