Friday, December 08, 2006

Winter Jasmine

The first spring blossoms are long weeks away. Even the optimistically-named Christmas rose (Helleborus niger) is still in bud, its touted winter blooms not yet open. Still, an early January walk in the gardens hereabouts will yield a treasure trove of some of the rarest of garden plants - the true winter flowers. Despite the negatives of winter weather - frost, heavy rains, and few if any pollinators active - this season features a hardy few flowers that have chosen it for their preferred time of opening. Winter jasmine is the truest of winter bloomers, opening first in December.

In our garden it begins early in December and is mostly finished flowering by Spring. Though the small leaves drop in Autumn, the stems remain green year-round, giving this shrub the effect of being evergreen. The cheery yellow trumpets are set off by this green backdrop. In full sun flowering can be heavy, and it can grow well in shade. Winter Jasmine is mostly indifferent to soil, doing well in rich or poor as long as drainage is at least fair. The growth habit is exceptional, and is best described as scrambling. In nature is weaves its way between competing shrubs until it finds a suitable spot to grow, and then scrambles some more. In your garden this gives you a plant that cascades well.

Winter jasmines unusual growth habit lends it to special design treatment. It can be used as a groundcover, or a broad low mounded shrub, but its starring role is to be planted where it can cascade down - from atop a wall, in a raised planter, above a slope the steeper the better, or tied to a tall post from which it can arch down. At a local hospital, a planting of winter jasmine cascades down 25 ft. from 2nd and 3rd floor planter boxes. We have this shrub (pictured) falling down a 10 ft. north facing wall. It only took two years to reach the bottom.

Try interplanting this with spreading groundcover roses to get color winter and summer.

Almost all jasmines are fragrant and many winter flowers are too, but winter jasmine is without fragrance.

Generally expect winter jasmine on flat ground to grow loosely to 18-24 inches high with a 10 foot spread. Be prepared for it to root as it goes, so that its potential for spreading is much greater than that of a single plant. For example, the pictured plant in my yard has rooted at the bottom of the wall. Recently rooted stems are easy to remove, to be tossed, transplanted or given away; cutting off the stems before rooting is simple too. If they are let to get well established they become more and more of a project to get out as the years pass!

The closest relative of this plant is forsythia. The two share flower color and shape, early flowering times, the tendency to root at branch tips, and an origin in China. Winter jasmine hails from the provinces of Gansu, Shaanxi, Sichuan, SE Xizang, and NW Yunnan. It is found in thickets often on steep ground, at elevations from 2600 to 15000 ft. (800 to 4500 m). An interesting trait is that this jasmine produces quarter inch (6 mm) berries. It never does so in the West because all plants of winter jasmine originate from a single 1844 introduction - which needs a pollinator which was left behind in China.

Botanic name: Jasminum nudiflorum
Gardening experts seem to differ greatly on the hardiness of this shrub - is it hardy in USDA zones 4 to 8 or 6 to 10 or somewhere in between? The Heat zone range is 1 to 8 or 9. Growth rate is moderate to fast.

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