Tiarella

Botanical/Latin
   Tiarella

Pronunciation
   Tie-ah-rell-ah

Common Name
   Foamflower

Hardiness zone range
   4 - 9

General Comments
Wonderful ground covering plants for shady, evenly moist places. In spring, they are covered with multitudes of little white or pale pink flowers shaped liked bottle brushes. They are carried in such profusion that, from a distance, they look like a layer of foam covering the rich green foliage. The leaves (which are almost evergreen in mild zones) of some highly prized forms have attractive, dark patterns that make a stunning foliage effect and they will often take on shades of maroon as the cooler temperatures of autumn arrive.

Uses
They are immensely useful as low ground cover in shady beds, frequently used under larger trees and specimen shrubs or on the shady side of buildings. The attractive foliage and flower features allow them to be used either as small clumps towards the front of beds and borders, as edging along paths, walls or fences, or in bold drifts in woodland gardens. They are ideal in natural style layouts and wild flower gardens.

Light Preference
Shade to Partial shade

Culture
Reliable and easy to grow, they perform best in loamy, humus rich soils that are well drained and have the capacity of retaining moisture in summer. This can be enhanced by adding compost or other humus media at planting time, and mulching after planting.

They are not troubled by any serious pests or diseases, and require very little maintenance. Watering during dry periods, and a light dressing with a well balanced fertilizer in spring, helps to keep them healthy and lush. If desired, established clumps can be divided in either early spring or fall, replanting the crowns about 12-15 inches apart.

Background
One species of Tiarella is found in Asia, but the most important garden worthy ones are natives of North America. They are found as shady woodland dwellers growing in humus rich, moist soils in several parts of the continent, but mostly down the eastern side, from Canada south through the Appalachian and Allegheny mountains to the southern states. It is generally accepted that about 7 different species exist, although some botanists believe that some are in fact forms and sub-species. T. cordifolia was the first to be collected and introduced. It is a pretty wild flower that was admired by early settlers who, in the different regions, gave them descriptive common names that included "Nancy-over-the-ground" referring to its spreading habit, "colwort" which described its early use for treating burns and scalds and, of course, "Foamflower".

As recently as 1937, Edgar Theodore Wherry discovered a form that grew in clumps (doesn't run) and had pinkish flowers. It was named after him (T.wherryi). Its introduction sparked an interest in these little plants that has developed and gained momentum in recent years. Wild populations show considerable variation, and recently several exciting new forms with bold leaf markings and pink flowers have been introduced; the Cultivar T `Spanish Cross' is one of our favorites.

Breeding and selection continues, and several promising new cultivars are likely to emerge in the next few years, so watch this space.

Splendor Suggestions
If your beds are likely to need watering during dry summer periods, consider "snaking" some soaker hose around the base of the plants. This is an effective way to supplement the moisture content, encourage more flowers, and keep them lush and vigorous during the critical dry periods.

A mulch applied in spring will also help retain the moisture; the ground covering foliage will help to disguise the unsightly look.

Companion Plants
Other good woodland partners would include the early spring flowering Helleborus `Royal Heritage', Ferns, and Hostas. We like the big, bold, frosty blue leaved Hosta `Krossa Regal' or `Blue Angel', or on a smaller scale `Blue Cadet' or `Halcyon'. Blue and white Campanulas and Veronicas (the white `Icicle', pink 'Minuet' and the cool blue of 'Goodness Grows' or 'Sunny Border Blue') are also fine companions. Where foliage contrast is required, try some of their near relatives; Heucheras like 'Plum Pudding', `Palace Purple' or the inter-specific hybrid X Heucherella 'Bridget Bloom'.