Shrubs sent haywire

Press, 9 March 1984, Page 14

Shrubs sent haywire

jARDENER’s! [ DIARY

Derrick Rooney

Growth of shrubs generally has been phenomenal this season, but the warm weather of the last days of February and early March, after a generally cool and sunless summer, has driven the growth patterns of some ha;

tywire. In my garden Viburnum farreri, which usually flowers in autumn, is not showing any buds yet, but its hybrid, Bodnantense, is flowring precociously. While pushing through a tangle of unstaked black raspberries (some of the canes have grown 3m high this year) the other day in search of a dwarf apple tree which had disappeared behind a tangle of greenery, I came across my bush of Bodnantense liberally sprinkled with little sprays of its fragrant pink flowers, half-hidden among the leaves. Usually these do not appear until winter, when most of the leaves have dropped. Next to it a ninebark (Physocarpus capitatus), a western North American shrub belonging to the rose family, is prettily covered with reddish fruit, which in a week or two will have disappeared underneath an unscheduled autumn flush of growth. For all I know this may be normal behaviour for the ninebark in the streamside shrublands which are its natural home, but it is not normal behaviour in my garden, where it has usually completed its annual growth by flowering in late midsummer and by mid-March is preparing to turn yellow for autumn. But this has not been a normal season.

It has been an erratic season which has not made life easy for the gardener. In the rock garden a number of dwarf shrubs, from which I took cuttings at the week-end, had ripened their growth so thoroughly that I felt obliged to use the rooting solution at hardwood strength. In the borders, however, a number of shrubs which I want to multiply are still flushing,

and have shoots so soft that it would be a waste of my time to take cuttings from them — at this stage. In a “normal” season these shoots would have firmed

up by early February. A curious effect of this season’s weather has been its influence on the growth patterns of a number of shrubs which in Canterbury usually have only one period of flushing in a year, and are expected to make the sturdy, short-jointed growth which makes many Canterbury-grown shrubs appealing. My viburnums, ninebark, cistuses and other shrubs, most notably rhododendrons, have the sort of succulent, whippy growth more often associated with the softer and wetter climates of the North Island.

It will be interesting to see how well, or whether, some of these flower next summer. Cistuses, for example, are hardy Mediterranean shrubs which are tolerant of and even expect a dry period in summer, because in their natural environment most of the rain falls in winter and spring.

Even native Canterbury

shrubs have made phenomenal growth in some gardens. x My koromiko (Hebe salici’Ttolia) bush is fairly bursting at the seams. A slip of a seedling only a few inches high when I planted it about five years ago, it has gone from waist high last year to well over head height. When

I pushed past it at the week-end in search of cuttings from my special form of Cistus laurifolius I found that the latter, too, had gone from waist to head height.

I should like to dwell a

little on this cistus. Of all the hardy evergreen

summer-flower shrubs that I have grown, this has, I believe, the most sumptuous flowers.

Imagine if you will a flower as big as a saucer, pure white, softly smudged with yellow at the eye, and with some of the rumply texture and sheen of a Victorian silk dress. At any one time during early summer there may be dozens of such flowers on the bush. Each flower lasts one day only, but new buds form, it seems overnight, and waves of colour come over a period of several weeks. The shrub came to me labelled “Cistus large white,” and it was several years before I was able to get a name to put to it. Mr W. R. Sykes, of the D.S.I.R. Botany Division, identified it as Cistus laurifolius — a species which usually has much smaller flowers. This is a shrub which deserves to be more widely grown, and to have a cultivar name to distinguish it from its drab brothers and sisters. For all I know it may have this honour overseas. The nursery from which my plant came no longer has stocks, and the owner cannot recall where his plants came from.

Doubtless it will surface again in commerce,one of these days. I advise shrub enthusiasts to keep an eye open for it. It may be a large white, but it is not a pig in a poke. In the rock garden, two little late-flowering bulbs have given a deal of pleasure in the last couple of weeks. Both are South African, and both have yellow flowers. Neither is so tall that a geriatric ant could not climb over it. They are Oxalis lobata and a romulea species whose name I was once told, wrote down, and lost. Little Oxalis lobata, which is South African, makes tufted, trefoil-like clumps, only a few centimetres high, and is a bit of an eccentric in that it frequently has two periods of growth and two dormant

periods in a year. Leaves and flowers appear together in the autumn. If the winter is a cold one the plant retreats underground until spring; when fresh tufts of foliage appear. By the beginning of summer it has died down again, a very sensible arrangement which ensures that the bulb receives maximum protection against both seasons of extreme weather.

I have always liked this little bulb, not least because it is one of the few oxalis species which can be grown even in the smallest of gardens at no risk whatever of an invasion. Some oxalis are bad weeds, but not all members of the genus are tarred with the same brush. Oxalis lobata likes a sunny place, and bare soil above it in summer — it soon dies out if its spot is overgrown. The flowers, when they come, are worth the effort of leaving that bare spot. Bright yellow, with a sheen, they open flat and are up to 2cm across, quite large in relation to the size of the plant. There is only one fault, and this is a fault common to many bulbs of South African Origin: the flowers open only on sunny days. The romulea entered my garden, if I recall rightly, as an “impurity” in a bag of crocus bulbs (crocuses and romuleas are fairly close but the romuleas are more southerly n their distribution and mostly summerflowering). It is a delightful little thing which flowers unexpectedly out of the bare ground in early autumn. The leaves are thread-like and the stemless flower nestles right down among them.

The flower is funnelshaped, the size of a thimble, and it, too, opens only on hot, sunny days. When it does open its brilliance is out of proportion to its size. The yellow is exceptionally rich and vivid — the colour an egg yolk ought to be but never is when you buy your eggs from the supermarket.