Dear Helen: I have some clumps of small ornamental grasses in my rockery and wonder if they should be cut back or just left to grow. If they should be cut back, is there a right or wrong time to do it?
K.M.
Leave all ornamental grasses untouched until late winter or early spring, when they will need either a grooming or a cutting back depending on the type of grass.
Deciduous grasses that have lost all the colour in their leaves should be cut down close to the ground at the end of winter, before fresh new growth appears. Cut the smaller ones down to five centimetres, the larger grasses down to around 10 cm. Examples are Miscanthus, Molinia (moor grass) and Pennisetum (fountain grass).
Evergreen grasses, that is those retaining colour in most of the leaves, are not cut down but just combed through and given a light leaf tip trim if needed. I comb through my sedges (Carex) using a claw cultivator, but a rake or large comb could also be used.
All my Carex plants are the low growing types that form dense, arching tufts of brown, bronze, blue, yellow, green or silvery leaves. Some are variegated. A green sedge called 鈥淭he Beatles鈥� was named for its mophead of foliage. These are close to maintenance-free grasses. A quick comb-through and a trim, followed by an early-spring mulching with compost, is all the care they require.
Dear Helen: On a recent BBC radio program, I heard about Strobilanthes atropurpurea, a hardy perennial that sounds intriguing. Have you heard of it? Is there a Canadian seed source? Do you order any seeds from the U.K.? Plant World Seeds in Devon is the only source I鈥檝e found.
S.J.
I was unfamiliar with this plant name until your question introduced me to it. Thank you. And yes, I send orders every year to both Plant World Seeds (PWS) and Chiltern seeds in Oxfordshire. I鈥檝e not found a Canadian seed source for Strobilanthes. This is a relatively little known plant. Few of my references on perennials list it.
Chiltern lists Strobilanthes atropurpurea, describing the 90-cm hardy perennial as 鈥渁n attractive plant with a purplish tint to its foliage, and bearing in July and August terminal spikes of purplish-pink, tubular flowers.鈥�
Though it鈥檚 not listed in the PWS print catalogue, S. atropurpurea is easily found in their online catalogue, which has over 3,000 listings, compared with the print catalogue鈥檚 500.
The online catalogue lists four forms of Strobilanthes and describes S. atropurpurea as producing a sturdy dome of stems bearing salvia-like leaves. From July to October, white buds inflate into masses of deep violet flowers shaped like rams鈥� horns.
S. atropurpurea 鈥楤lue Lips鈥� is a new listing with two-toned flowers in white with blue lips. S. attenuata, another 鈥渨elcome newcomer,鈥� is a dwarf form at 45 to 60 cm with curved, tubular violet flowers produced over 鈥渁 long and valuable flowering season, usually until October or even later.鈥�
S. nutans is the most unusual, one I think I鈥檒l be ordering. It produces a 鈥済reen igloo of leaves鈥� and pendulous (nutans means nodding) tassels of white, trumpet-shaped flowers in summer and autumn.
The Chiltern Seeds catalogue can be ordered from their website. The people at Plant World Seeds tell me that they have stopped sending print catalogues to overseas addresses, but will send them out along with a received order.
I鈥檓 aware that not everyone has online access. In that case, here鈥檚 what to do if you desire a print catalogue: Enlist help from a friend, neighbour, or someone at your local library in finding a search engine to access the Plant World Seeds website. Order something you know you鈥檇 like to grow. An order number will be sent back to you. As soon as you receive it, email [email protected]. Quote your order number and mention that you鈥檇 like a paper catalogue added to your order.
I鈥檝e chosen to include your question about a relatively obscure plant in a column because this is the precise time of year to stir up enthusiasm for horticultural adventure into the unknown. Personally, I make it a practice to try growing at least one unfamiliar plant from seed each year, preferably one whose name I鈥檇 never heard of. Thanks again for introducing me to Strobilanthes.
