Our cover star: Carol Klein
It’s not always important to know lots of botanical terms and definitions, but sometimes it helps us to grow be er plants if we do. Carol Klein explains all on
Botanical terms and definitions aren’t always important. Many a brilliant gardener plies their trade without technical terms ever entering their heads. Gardening is so much about common sense, intuition and experience.
Sometimes though it’s useful, not just academically, but practically, to understand some of these terms. I’m no expert as I’ve no horticultural training whatsoever apart from doing it – gardening and running a nursery for more than 30 years. Nonetheless, the nomenclature of plants and the divisions into which they’re placed are eye-opening.
Bulb is a term we all use, especially at this time of year when we begin to peruse catalogues laden with page after page of photos of tulips, daffodils and crocus. But what am I saying, crocus aren’t bulbs – they’re corms!
At first sight corms look like bulbs – think crocus, gladioli or crocosmias. In fact, they’re solid, though often covered in a papery outside layer. New stems emerge from the top of the corm, usually turning themselves into a flower, though they can also produce underground stems that go on to make new corms. Many of them
Learning more about bulbs, tubers, corms and rhizomes enables us to grow them better
make new ones on top of the old.
Anyone who has dug up a congested clump of crocosmia will have found strands of corms, growing one on top of the other. It’s a good idea to snap off the uppermost corm and replant in a new place, having added plenty of organic matter. You can do this in late autumn if your soil is free-draining but if you’ve cold, wet clay, it’s better to wait until the following spring. Cover with a couple of inches of soil and plant in random groups.
Unless you’re growing straight rows of gladioli for cut flowers in the veg garden, the general rule for most bulbs and corms is try to plant in a naturalistic, informal way.
Some bulbs and corms, though, lend themselves to container culture. Acidanthera or, as they’re now called, Gladiolus murielae, are perfect in pots. They flower late and are often at their best in September and October. With a bit of warmth they exude a glorious scent in the evening.
Tulips are perfect subjects for pots, too, and if your soil is heavy clay, like ours here at Glebe Cottage, it’s sometimes the only option. Tulips are true bulbs. Bulbs are essentially made up from the leaves and flowers they’ll eventually produce. They all have a base plate, a compressed stem, from which their roots emerge. Most bulbs are tunicate, with layer upon layer wrapped round themselves, and onions are a typical example. Some bulbs, such as lilies and fritillaries, consist of separate sections, or ‘scales’.
One of the purposes of bulbs and corms is to store the starch and protein needed to support growth when conditions are right. The same is true of tubers and rhizomes, too.
Another vegetable, the potato, is a good example of a tuber. In common with dahlias and cyclamen, it develops its tuber from stems or roots. These roots go out to gather nutrients and water and shoots radiate to form flowers and leaves.
Rhizomes are similar. Their underground stems swell up, producing roots on their undersides and shoots from the top. Ginger is a good example with edible rhizomes, and flag iris, some of which produce rhizomes still used in perfumery as a fixative, is another.
Whichever category they belong to – bulbs, tubers, corms or rhizomes – they’re all wonderful examples of how organisms have evolved to cope with specific conditions, and learning which they are enables us to grow them better.