Short burst of mallow yellow in springtime
Kerria japonica, AKA Jew’s mallow, is a very easy-going shrub which will grow in just about any soil and any situation (although it may sulk if it’s planted in a wind tunnel).
People plant it, enjoy its early floral show and then worry about what has gone wrong when the blooms diminish in number while the stems and foliage increase in vigour.
For most of the year it is a bit twiggy and uninteresting, but for a few weeks in spring it should be a little ray of light.
Accept it as a gift from Mother Nature and enjoy it for what it is – a trouble-free, rather lax, multi-stemmed shrub designed to bring a vivid splash of colour to compete with all the other yellow-blooming shrubs and flowers as winter finally draws to a close.
The flowers appear in April and can continue into May – and you may be
fortunate enough to get an occasional sporadic second flowering.
The most popular variety is the doubleflowered form, K japonica “pleniflora”, which can reach almost 10 foot in height, so it’s sometimes trained to grow up walls or trellises.
It’s a deciduous shrub in the rose family, native to China, Japan and Korea, and is named after William Kerr, the renowned Scottish gardener and plant-hunter, who introduced the “pleniflora” cultivar.
Kerria will grow in any average, welldrained soil. It doesn’t mind shade. In fact, too much sun will bleach the yellow out of the flowers.
The biggest problem is that it’s a bit of an untidy shrub, so it pays to prune it in June, removing all the shoots which have flowered – kerria blooms on the previous year’s wood, so prune after the flowers have finished. This treatment is essential to encourage flowers; be kind and considerate and it will result in plenty of greenery but fewer blooms.
Propagation is simple – pull up rooted pieces or plant cuttings in a cold frame in summer. They should strike fairly quickly.