Heucheras And Their Friends by Martin Blow
Heucheras and their friends, tiarellas, are among the most popular foliage plants for a shady garden these days with lots of new varieties, new leaf colours and patterns being introduced each year. However, heucheras started their horticultural story being grown and bred for the cut flower trade with masses of pink, white or red bells along stiff wiry stems up to 2½ft / 75cm long.
Heucheras and tiarellas are still valued for their flowers but new varieties tend to produce far shorter stems and sometimes the flowers are insignificant with the interest coming solely from the leaves. Heucheras and tiarellas are so closely related that they can cross pollenate creating the heucherella hybrids. Tellima is another closely related plant represented by a single species “grandiflora”. These are unassuming plants, but tough and long flowering with fringed bells in greenish white with a ruby red edge.
Heucheras, tiarellas, tellimas and their hybrids are all woodland plants and shallow rooted so do best in humus-rich soils that retain some moisture in summer and are partly shaded from the hot sun. Some shade is essential for those with the most highly coloured leaves to avoid scorching. I find that tellima is more drought tolerant and takes deeper shade than the others. None like being waterlogged in winter.
Propagation is by division (essential for named varieties) in autumn or spring or by seed sown in heat for the species and for raising new varieties, but germination can be slow.
In early spring give the plants a good tidy up, removing dead, damaged and old leaves. You can also cut back hard and untidy woody shoots. The tips of the shoots can make cuttings for new plants. After a few years heucheras and heucherellas tend to form an almost woody mass as their base and produce untidy growth; so, lift and divide, replanting the young shoots which will quickly root. Tellimas and tiarellas seem less prone to becoming woody.
Another, less enjoyable, spring task is to check for vine weevil grubs feasting on the roots. If the leaves are small, dry or browning at the edge and the plant is not firmly rooted then pull it out and search the soil for the small, brown-headed, legless white grubs and destroy them or feed to your garden robin. This is particularly a problem in wet soils or when growing in containers. In containers you can use a biological control in the form of microscopic nematodes watered into the soil. You need both a summer and a winter type to get complete control.
In summer remove spent flower stems by breaking them off at the joint with the plant rather than cutting as this encourages repeat blooming.
Heucheras and their friends blend well with other garden plants and flowers and give interest throughout the year. In spring the fresh growth is highly coloured; in summer and autumn, flowers enhance the show and in winter the leaves edged with frost give a magical, glittering effect. Coupled with the ease of propagation and constant stream of new varieties they are a good buy for the garden and pot culture and light up many a shady spot.
Janet & I run Special Perennials, our website www.specialperennials.com is full of colour photos and growing tips. We also organise Plant Hunters’ Fairs, specialist plant fairs at wonderful locations including Middleton Hall, Nr Tamworth, B78 2AE and the 1620s House and Garden, Donington Le Heath, LE67 2FW. For details of these and all other Plant Hunters’ Fairs coming up during 2021 please see www.planthuntersfairs.co.uk.