Bizarre ways to produce flowers

Press, 21 October 1983, Page 19

Bizarre ways to produce flowers

GARDENER’S W DIARY

Derrick Rooney

Gentiana acaulis, the great stemless gentian, was named by Linnaeus in 1753, so it has been in cultivation for a good deal longer than two centuries. For most of that time, generations of gardeners have struggled with the problem of how to make it flower.

Almost as many explanations for its rectitude in many gardens have been advanced as there are alpine gardeners. The lack of flowers has been ascribed to senility induced by continual vegetative propagation over the years; to the presence or absence of lime in the soil; and to various climatic or soil deficiencies. Recipes for making it flower are legion. They include stamping on the soil around the plant until it is concrete hard; tearing the plant to pieces and replanting it every second year; planting it in Port Hills clay, planting it in peat; feeding it with lime; and various other bizarre proposals. I have listened to many over the years and tried a good few, and my opinion, for what it is worth, is that none of them is worth a damn. My recipe for success with Gentiana acaulis is simply this: keep trying different clones until you find one which flowers in your garden.

The plant is such a cussed thing that even if you buy it from a nursery where it flowers freely you cannot be sure it will do the same in the garden. In fact, it may never flower again. This is precisely what happened at the start of my Gentiana acaulis story. After four flowerless years I scrapped the bought plant and got a piece of another from a friend in Governors Bay. In his garden it flowered profusely, not only in spring but frequently in autumn also. I grew it for 10 years, and never had a flower. Gentian No. 3 came from an inland garden at 1200 ft, where it grew so luxuriantly that the owners forked out and composted large clumps every year. In early summer their garden became a sheet of blue. They dug out a generous clump complete with flowers and buds, and I took it home to my new rock garden — where it never flowered again.

Then I bought, from the

North Island, a plant named Gentiana angustifolia — really just acaulis a shade paler, and a reminder that no-one really knows the origin of the long-cultivated species named by Linnaeus. Gentiana acaulis, in the form grown in gardens, is not known to exist as a wild plant; and the name has become a sort of umbrella to cover a dozen or more closely related species, including angustifolia, from all mountainous parts of Europe. No wonder the poor thing refuses to flower — horticulturists and botanists have it so muddled up that it doesn’t know whether it’s Arthur or Martha.

Gentiana angustifolia was guaranteed by the nursery to flower, and flower it did, in both spring and autumn, for three years. Last year it suffered from overcrowding when some neighbouring plants (including a hebe, since removed) got too big for their site, and as a result it is not flowering much this spring. But I look forward to a resumption next year. If this doesn’t happen, no matter, because now I have, wonder of wonders, a Gentiana acaulis which is flowering more prolifically with each passing year. The provenance of this plant is a mystery — I acquired it one night from the sales table at an alpine society meeting and no-one seemed to know the identity of the donor. A single flower bud was showing at the time of purchase.

After two summers in the rock garden the size of the clump hasn’t altered much, but the number of buds has multiplied to nine, which are either open or half open now — a glorious sight. It is “genuine” acaulis with huge deep-blue bells, marked with green spots inside and deeper blue in the throat. Was it worth the 15-year wait? Definitely!

The soil mix in which it is growing, incidentally, is turfy loam (which had been stacked a couple of years where poultry could pick over and scratch in it), grit, and peat. No lime! Gentiana angustifolia, on the other hand, seems to respond to an occasional dressing of dolomite. The truth about Gentiana acaulis and lime is thus revealed: the diversity of plants which come under this umbrella are from many parts of Europe, and naturally some are from limestone areas, and some from non-limestone areas. The former are used to having lime in the soil, the latter aren’t. It’s as simple as that.

Actually, I could have avoided all these hassles over Ume and flowering if I had just had Gentiana verna a few years earlier. This is another umbrella name which covers a clutch (or is it several clutches) of small European mountain gentians.

Their flowers are quite small, only a centimetre or two long, and open flat at the mouth, but their colour

is electrifying: a clear, penetrating azure blue. Everyone who sees the plant wants to grow it. Unlike its larger cousin, Gentiana verna will flower with reckless abandon in anybody’s rock garden. But it is not without faults. It is often short-lived, and it resents, even more than do most other gentians, being lifted from the ground and torn to bits. Cuttings do not strike readily. Seed is the only ready means of increase, and fortunately there is usually plenty of it on a flowering clump. If collected when ripe and sown in pots fairly soon afterwards, the seed

comes up like mustard and cress.

This is a case where man can improve on nature by giving a helping hand: the same seeds, if left to shed naturally on to the soil around the parent, are unlikely ever to germinate. I don’t know quite why this should be so.

Other alpines have a penchant for seeding themselves into all sorts of nooks and crannies, but in my rock garden Gentiana verna is staying put, while all around it seedlings of a supposedly much more difficult Aretian androsace, growing nearby, are coming up by the dozen.