Rudbeckia Rudbeckia - Coneflowers - which sometimes include the Echinacea, but we give them their own section. Flowering from mid-summer through until the autumn frosts with mainly golden yellow daisy flowers. Invaluable for the late autumn period which can be so dull.
Ranunculus - To call the ranunculus group of perennials simply 'Buttercups' does it a great injustice. The parent group of Ranunculaceae is huge and all sharing the same floral makeup of five petals - or multiples thereof. There are many perennials by name of Ranunculus , and room in every garden for at least one. In all probability you will have some plants from the parent group growing in your garden, with different names to Ranunculus.
Rehmannia - Tubular flowers that open out to a well-lipped bell - akin to foxglove flowers. Herbaceous perennials, with attractive foliage and distinct types that can grow as small as 15cm or to a substantial 1.5m tall.
Rheum - Ornamental Rhubarb - This can make a stunning specimen plant, with large - sometimes bronze leaves - and a tall loose spikes of small flower clustered above the foliage. Dappled shade is best, and have seen it grow well in dry and moist soil types.
Rhodiola - Fleshy foliage (It is a Crassula) flower plates not unlike the Sedum spectabilis plants - It is sometime called Sedum. Best suited to sunny situation, and dry rather than moist growing conditions.
Rhodohypoxis - Cormous root system for these clump forming herbaceous perennials. Whilst they are much hardier than they might look, they fully resent cold wet roots in winter. A good well drained dry spot is the place - with full sun.
Rogersia - Good clump forming specimen plants for dappled shade or full sun. very 'architectural' if you are into 'shape' gardening. Pinnate leaves - sometimes deeply veined - with tall panicles of loose flowers held above. Height and spread varies with the different varieties, but not normally less than 90cm height and spread.
Romneya - A Tree Poppy. Some call these sub-shrubs. we are happy with the perennial tag, for they are herbaceous plants. Mainly glaucous foliage, and super white poppy flowers with central yellow spot well highlighted. Height to 2m but not taking too much room at ground level.
Roscoea - Not entirely convinced about the hardiness of this group, unless you live in a sheltered area. Interesting drooping open tubed flowers if you succeed. Foliage is similar to that of the Tulip. They are tuberous perennials - a good idea to apply a mulch in the autumn.
Ruta -Rue Shrub, sub-shrub or perennial (you
can choose.) Whichever, it is widely grown in herbaceous borders
and particularly useful for its steel grey foliage. It is also grown for
its herbal qualities as well. A very pungent aroma if the foliage is
crushed, together with which it can cause skin irritations.