Tiarella

( tye - ar - RELL - uh )

At-A-Glance Information

Tiarella, commonly called Foamflower or Sugar-Scoop, is a genus of plants which need partial to full shade and regular water to perform well. Plants form clumps 1.5 feet tall and a little wider, and spread by rhizomes or above-ground runners. They are evergreen, though foliage still changes color in fall. Upright flower stems hold small white or pink flowers. Foamflower is useful in shade gardens, and they also make delicate groundcovers in areas that do not get any foot traffic. Use Foamflowers in mixed beds and borders in cottage, informal, pollinator, native, woodland, and shade gardens.

Tiarella Species and Varietals

The genus Tiarella is a member of the plant family Saxifragaceae and includes 7 species. The genus name means 'little turban', referring to the shape of the seed capsules produced after flowers have faded. Foamflower growing zones vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Tiarella austrina (Southern Foamflower)
These plants are native to the southeastern United States, and spread via underground stolons to form colonies. Leaves are green, and are large at the base of the plant, getting smaller as they go up flowering stems. At maturity, plants in this species reach up to 16 inches tall and forms clumps to 12-24 inches wide.

Tiarella cordifolia (Heart-Leaved Foamflower, Allegheny Foamflower, False Miterwort, Coolwort)
This species grows in zones A3, 1-9 and 14-24 and is native to eastern areas of North America. Leaves are light green and turn red and yellow in fall. Flowers are cream colored and bloom on foot-high flowering stems. Varieties include 'Oak Leaf' (with deeply lobed leaves and pink flowers) and 'Running Tapestry' (with deeply lobed leaves and dark purple to maroon veining).

Hybrid Tiarella
This group of Tiarella grows best in zones 1-9 and 14-21; they are described below.

'Cygnet'
Leaves are star-shaped with purple markings and flowers are white, opening from pink buds.

'Mint Chocolate'
Leaves have deep lobes and are blushed with a deep brown-purple. Flowers are pink-white.

'Neon Lights'
Leaves are bright green, large and deeply cut with blackish centers.

'Pink Skyrocket'
Large, light pink fragrant flowers and deeply cut leaves that have a black central spot. Leaves turn almost completely black in wintertime.

Tiarella nautila (Sail-Leaf Foamflower)
The species is endemic to the Blue Ridge Mountains in the southeastern United States, and is named for its sail-like stem leaves. Flowers are white to light pink. Plants reach up to between 6 and 12 inches tall and 12 inches wide when mature and in bloom, spreading via rhizome roots to form colonies over time.

Tiarella polyphylla (Asian Foamflower)
This species is native to Asia, and is a perennial herbaceous plant that produces spikes of small, whitish flowers with no petals. At maturity, Asian Foamflower plants reach up to 6-12 inches tall and a foot wide. They will form clumps over time, and are great for naturalizing in woodland borders.

Tiarella trifoliata unifoliata (Tiarella unifoliata) (Sugar-Scoop, Western Foamflower)
Best in zones A3, 1-7 and 14-17, this species is native to Alaska down to California and east to the Rocky Mountains. Leaves are dark green and divided, and flowers are white and bloom on 1.5 foot tall stems followed by fruits that look like scoops of sugar.

Tiarella wherryi (Tiarella cordifolia collina) (Wherry's Foamflower)
This species grows well in zones 2-9 and 14-21 and is native to the southeastern United States. It is slower to spread than other species, and flower clusters are more slender, often tinged with pink.

Caring for Tiarella

Tiarella plants can be grown from seed or purchased as starts or specimens from a reputable nursery. They are considered a wildflower, and over time will form colonies through spreading root systems and also by reseeding. They appreciate a space in the garden that receives partial to full shade. They are naturally woodland plants, and can only take direct sun in the morning. Foamflowers like a soil that is well-draining and fertile, amended with plenty of organic material. They grow well in soils with a pH of between 5.5 and 6.8 (slightly acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, Tiarella appreciates a consistently moist substrate, but does not do well with standing water around roots. They can tolerate very short periods of drought.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. Leaves on Tiarella species are evergreen, but will change color when cooler temperatures come around in fall. In springtime before new growth begins for the year, prune plants back to remove dead, damaged, or diseased foliage. If you are growing Foamflowers in cramped garden spaces (such as containers or small borders), they will need to be divided every few years. These plants form colonies via spreading rot systems, and division can help to ensure that all plants remain healthy. For instructions on how to successfully divide Tiarella plants, see the Propagation section below.

Propagation

Tiarella plants can be propagated either by division or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Foamflower, follow the instructions below:

Propagating Tiarella by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
Harvest your seeds. Cut off dried up flower heads from the plant that still have seeds and place them in a paper bag. Allow the seeds to release, and then remove them from the bag so you can work with them. If you will not be using your seeds immediately, store them in a cool, dry, dark place. They can remain viable for between 2 and 3 years if stored properly.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Tiarella by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring or fall (after the plant has entered dormancy and been cut to the ground, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the roots. Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divided plants and water thoroughly.
Apply a thick layer of mulch around the base of the newly divided planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout.