Posted on | August 23, 2013 | 4 Comments
It’s nearly the end of August and the evenings are drawing in fast, but thankfully many plants are only just coming to bloom or are now reaching their peak in time for the bank Holiday weekend. After open-days here at the Exotic Garden, all the garden helpers and I usually have a sunset meal outside where we can all enjoy the evening as the light fades into twilight, waiting for the first stars to appear. Just before the light fails completely all the flowers seem to glow with such intensity compared to the harsh sun of the day as does all the foliage which becomes rich dark green before the light fades completely into darkness.
I usually write this column on a Monday, following a walk around the garden for inspiration. There are always new plants coming into bloom and it also reminds me that I must keep up with dead heading all the flowers that have gone over – a very important job at this time of year if you want blooms right through into the autumn!
One family of plants that are flowering to perfection at this time of year are the Thunbergia’s and much appreciated by visitors. I have had a passion for this family of plants since I was a boy. I remember buying some Thunbergia alata seeds, more commonly known as ‘Black eyed Susan’. I loved their intense orange flowers with a deep, dark throat – so alluring. They were among the first seeds I bought from Thompson and Morgan when their catalogue had no pictures only descriptions with a fairly plain cover – anyone remember their 1960’s catalogues?
I still grow this easy annual to this day. They are actually perennial’s, which I have overwintered in a greenhouse at a min 5C, though I find that they grow so fast form seed that keeping them over winter isn’t really necessary. I have six or so large 15ins terracotta pots with a wigwam of four canes about 6 feet tall with a scaffolding of green garden twine surrounding the canes for support. All the canes come from the garden.
The seeds are planted in mid-April when the days are longer and the sun is stronger after the dull days of winter have passed. Planting the seeds too early makes the young plants stretched and week, a phenomenon called etiolation.
They are grown in plastic trays with individual cells so that they have little root disturbance when planted out, usually about five plants per pot depending on size. The orange forms are grown from seed collected here at the Exotic Garden in the autumn. They are rapid growers, reaching the top of the canes by July. The stems that stray are gently pushed back into the wigwam, where they soon twist around each other, forming a very attractive thin column, tightly packed with foliage. The flowers appear fairly early on in their growth but reach a crescendo at this time of year. If you want continuous flowers, it is advisable to pinch out the dying blooms before they go to seed. In saying that though, they produce seed very easily, so I let a few flowers go to seed so I have a supply for the following year.
Thunbergia is in a genus of about one hundred species of annuals, evergreen perennials, climbers and a few shrubs, found growing in woodlands or rocky areas, climbing through trees and shrubs in their native habitats of Tropical and Southern Africa, Madagascar and subtropical to tropical parts of Asia – I have often seen them growing wild on visits the Caribbean or in Botanical Gardens in the tropics, some reach gargantuan proportions like Thunbergia grandiflora that can cover large trees giving a breath-taking display.
The most commonly available and most well-known in this country is Thunbergia alata, Black Eyed Susan’, which grows up to 6ft or more in our climate with attractive triangular, slightly furry, mid-green leaves. The whole plant is covered from summer to autumn with masses of solitary five petalled flowers which are normally bright orange, yellow or white, either with or without a dark blackish brown centre, and can be up to 1½ins across.
Which to choose? Thunbergia alata ‘Beauty Spot’ is a range with three of the most gorgeous and delectable Black-Eyed Susan’s; orange, vanilla and pure white, all with a dark beauty spot. ‘Salmon Shades’ are very attractive, in varying shades of soft salmon, each with a distinct central black eye. Thunbergia alata ‘Superstar Orange’ is a spectacular bright orange. It’s an almost day-glow Black-Eyed Susan with the largest flowers in the range that can be grown from seed.
Later in the season, from late June onwards many garden centres stock some of the more interesting forms of ‘Black Eyed Susan’ that are grown from cuttings. They are well worth seeking out as they add such a unique splash of colour to the garden, especially if positioned either side of a doorway where they can be regularly admired.
There is now a good range to choose from such as Thunbergia ‘Sunlady’ which bears beautiful yellow flowers with sharply contrasting dark maroon to almost black centres. T. ‘Arizona Dark Red’ is a real smasher with intense brick red flowers that when in full flower produce a wall of intense colour. T. ‘Lemon’ is as its name suggests the brightest of Lemon Yellows. T. ‘African Sun’ has large dusky burnt pinkie-orange flowers. There are many more now coming onto the market with names like, ‘Orange Beauty’, ‘Raspberry’, ‘Red-Orange’ and a large pure white form with a deep black eye.
While on the subject of climbers, I must mention another easy perennial grown as an annual in the UK that is easily grown from seed, Rhodochiton atrosanguineum, more commonly known as the ‘Purple Bell Vine’. I have a large terracotta pot with the same bamboo cane structure I use for the Thunbergia’s, absolutely covered in flowers at the moment. This fascinating tender climber hails from Mexico and grows rapidly and from mid-summer until early autumn, is studded with long dangling flowers, each bloom is composed of a long, slender, purple-black tube growing out of a ballet-dancer like skirt mauve calyx. In a good summer (like this one) it can easily reach six or more feet in height covered in dozens if not hundreds of flowers.
Now it’s the weekend and the time to revel in your own garden, or if you fancy an afternoon out, the Exotic Garden here in Norwich will also be open on Bank Holiday Monday. Whatever you do, have a fabulous weekend surrounded by some of the best things in nature – Plants!