Slow to start but eventually filling the garden with colour these robust annuals are good all-rounders
Rudbeckia is a large and diverse genus, mainly North American, with many valuable garden plants among its ranks. They are closely related to Echinacea, which were once included in the genus and, although commonly called black-eyed susans, they are also called coneflowers because of the raised receptacle in the centre of the ‘flower, covered in dark disc florets. The ray florets are usually yellow or orange. Among the perennials are the tall R. maxima, bold but with flowers out of proportion to the plants (too small) and the hugely popular (and deservedly so) R. fulgida var. sullivantii ‘Goldsturm’. Also getting lots of publicity from time to time is R. occidentalis, a lanky soul with ‘flowers’ with no ray florets and a tall cone of black florets. Occidentalis means ‘westerm’ and this has a wild distribution in the west of North America unlike most of the species, including R. hirta, the one we are chiefly interested in here. Rudbeckia occidentalis is usually sold as ‘Green Wizard’ and as of great value to flower arrangers for the strange blooms with large green bracts around the blooms. I am not convinced of its merits, especially in the garden.
But back to R. hirta. This is native to eastern North America but has since naturalised in other areas and is the State flower of Maryland. It is a coarsely hairy plant with large basal leaves and is best grown as a half-hardy annual. It is theoretically biennial or a short-lived perennial. The joy of this plant, apart from the cheerful flowers, is that it is a robust plant suitable for bedding and adding to mixed borders. It is also a wonderful cut flower, lasting at least a week in a vase. The flowers are typically ‘single’ but there are doubles, in varying degrees and the colour range has increased to include browns and oranges and wine-red in ‘Cherry Brandy’ (below). Heights have also been ‘improved’, which means shortened, including the hideous ‘Toto’ which should be trodden on to put it out of its misery.
Apart from these dwarfs there are no bad rudbeckias. I like the full doubles and can just about tolerate the quilled types. The first I ever grew was ‘Marmalade’ which has a few more petals than single and is a decent height at 45cm – ideal for bedding and cutting. Although there are a few F1 hybrids and some expensive varieties, ‘Marmalade’ is inexpensive, as is the slightly taller ‘Rustic Dwarfs’. These are not at all dwarf and the mixture includes single colours and bicolours. It is my go-to pack when I need to fill an area with late summer colour.
I am also fond of those with dark areas around the eyes including ‘Kelvedon Wonder’ and ‘Aries’. They make spectacular cut flowers. Other good mixes include ‘Cherokee Sunset’ (above) but there are lots.
Rudbeckias are quite easy to grow from seed but they hate wet, cold, compressed compost so add perlite or grit to the compost. Seedlings can be slow after pricking out but once the weather gets warmer and the sun stronger they start to muscle-up a bit. Unlike most bedding plants there will be no sign of flowers when the leafy plants are ready to put out in the border. Despite the roughly hairy leaves the young plants are vulnerable to slugs and snails. With luck the plants will get bigger and, usually in August, they start to send up flower stems. Once the first flowers open the stems branch and a long succession of smaller flowers are produced. The flowers last for ages on the plants, if you don’t cut them. Although we grow these as half-hardy annuals they actually survive light frosts so keep the colour going right into autumn. THey may be slow burners but they are well worth the wait.