Question: I’ve seen trailers described as pendulous, spreading, naturally trailing, and semitrailing. Could you tell me the difference? How should they be grown?
Answer: These are terms adopted by some hybridizers and growers to describe the growth habits of trailing varieties. Unfortunately, these will differ somewhat amongst growers and catalog listings. This is partly because hybridizers don’t adequately, or accurately, describe their hybrids. Also, growth habit can be influenced by the individual grower–even if the variety is predisposed to grow differently. We’ve had customers show us their “trailing” violets–not a trailer at all, but one that had been allowed to sucker, develop multiple crowns, and which had never been repotted. After a number of years, the necks were long enough to appear to be trailing over the sides of the pot. Though this plant was trailing, it wasn’t a “trailer”.
“Naturally” trailing and “semitrailing” should refer to the way in which the violet is genetically predisposed to grow–i.e. not as a result of grower intervention. A semitrailing variety will most often grow in a shrub-like manner, with most of the branching growth being vertical. A naturally trailing variety will produce branching growth in a more horizontal manner–growing out along the soil surface, rather than up. In addition, though semitrailers often require pinching to induce a good trailing habit, naturally trailing varieties typically are more freely branching.
Naturally trailing varieties more easily lend themselves to being grown in hanging baskets (pendulous) or as ground covers (spreading) since, by nature, they will grow more horizontally. To grow as a “ground cover”, gradually move the plant into larger pots, so that branches, or runners, can grow along the soil surface. Be sure never to use a pot more than 3″ deep since, though the plant will continue to spread, its roots will never grow deeper than this. If a deeper pot is used, fill the bottom with perlite or other drainage material. To grow as a hanging basket, don’t go to a wider pot to accommodate the longer runner/branches–when they reach the pot’s edge they’ll begin to grow over the sides and hang! If’ you’ve got good window light, trailers can be spectacular grown this way. The trailing species violets grow very nicely as hanging plants. We’ve grown S. pendula kizarae in a window this way, and S. magungensis var. minima makes an excellent miniature trailer grown in either a saucer or hanging basket.
Semitrailers, on the other hand, will tend to grow as a small “shrub” in the middle of a wide, shallow, pot, since more of its growth will be vertical. These varieties look best when grown as small, bushy shrubs, rather than as ground covers or hanging plants. Use a pot only large enough to accommodate the plant–don’t overpot expecting to see runners that won’t be produced.