Ornamental · Saxifragaceae
Foamflower
Tiarella cordifolia
A native shade dweller that throws up frothy spires of white in spring and carpets the ground the rest of the year.
Partial shade
Every 3–7 days
USDA 3–9
5–12 in · 13–30 cm
Overview
Foamflower earns its name in spring, when slender spikes of tiny white to pink flowers rise above the leaves like sea foam. It's a woodland native of eastern North America, a member of the saxifrage family that spreads across the forest floor by creeping rhizomes and stolons. In the garden it does the same job, knitting together into a low, leafy carpet.
The heart-shaped, often lobed leaves are the real workhorse. They hold their color into winter as semi-evergreen foliage, and many forms flush with bronze or deep red veining as the cold sets in. Hardy from USDA zones 3 to 9, it shrugs off the kind of dense, dry shade where little else will flower.
What it asks for is simple: shade, steady moisture, and rich woodland soil. Give it that and it more or less looks after itself, spreading a little wider each year. Deer leave it alone, the pest list is short, and an established clump can be split for free plants every other spring.
Care
The short version: part to full shade, rich and humusy soil kept evenly moist, and good drainage through winter, with almost no feeding needed in decent woodland ground.
Light
Plant foamflower in part shade to full shade. It's a woodland plant that grows happily under trees and on the north side of a house, and it's one of the few flowering ground covers that performs in heavy shade.
Water
Keep the soil consistently moist and never let it dry out, since this plant has no drought tolerance. Watering every 3 to 7 days suits most sites, but ease off in winter, because soil that stays wet through the cold months can kill the crown.
Soil
Give it rich, humusy soil that holds moisture yet still drains, the loose leaf-litter ground of a forest floor. A pH of 6.0 to 7.0, from slightly acidic to neutral, is the sweet spot, so work in plenty of compost or leaf mold before planting.
Humidity
Ordinary outdoor humidity is plenty, with no number to chase. Steady soil moisture matters far more to foamflower than the air around it.
Feeding
This is a light feeder that does well in good woodland soil without much help. A thin topdressing of compost or a balanced fertilizer once during the growing season is all it wants, and heavy feeding does nothing for it.
Pruning
Pruning amounts to a quick tidy. At the start of the growing season, cut back any tattered or winter-damaged foliage, and fresh leaves push up to replace it.
Size & spacing
Plants stay low, reaching 5 to 12 inches (13 to 30 cm) tall, and slowly spread to 12 to 24 inches (30 to 60 cm) across. Set them roughly a spread apart and they'll knit together into a continuous ground cover.
When to plant
Foamflower follows the rhythm of the woods. Set new plants out in spring or early fall while the soil is cool and damp, and the flower spikes rise in spring, peaking in May before the leaves take over for the rest of the year.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Late winter; seed germination can be slow and plants are largely self-incompatible.
- Plant: Spring or early fall in shaded, moist sites.
- Harvest: Blooms in spring, peaking in May, with spikes of small white to pink flowers.
Hardiness
USDA hardiness zones: 3–9
Temperature: down to -40°C
Troubleshooting
Foamflower stays largely trouble-free, and most of what does go wrong traces back to the soil being too dry or too wet. Read the early signs in the leaves and crown, then act before a small problem spreads. Match what you see below to find the cause.
Crowns rotting and plants collapsing over winter
Standing wet through the cold months is what kills foamflower, not the cold itself. Waterlogged ground brings on crown and root rot, and you'll find the crown gone mushy and discolored where it should be firm. There's no saving a rotted crown, so cut your losses, dig out the worst of it, and either work in organic matter to drain the bed or move the plant somewhere it won't sit in water.
Fix:
- Improve drainage by amending with organic matter
- Relocate to a better-drained site
- Remove and discard rotted crowns
Leaves wilting and browning in hot, dry spells
Foamflower has no tolerance for drought, and the foliage browns fast once the soil dries out. Push a finger a few centimeters down to check, then water deeply to bring the moisture back. A blanket of leaf mold or compost mulch holds water in, and a little extra shade through the hottest part of the day takes the edge off.
Fix:
- Water deeply to restore even moisture
- Apply a layer of leaf-mold or compost mulch to retain moisture
- Provide additional shade in hottest part of day
Notched leaf edges and plants that weaken or collapse
Clean, C-shaped notches bitten out of the leaf margins point to the black vine weevil. The adults chew the edges at night, but the real harm comes from the larvae below, white legless grubs that eat the roots. Check the leaf edges and dig a little to find the grubs, then drench the soil with beneficial nematodes and hand-pick or trap the adults after dark.
Fix:
- Remove and destroy affected debris
- Apply beneficial nematodes to soil for larvae
- Hand-pick or trap adult weevils at night
Toxicity
Good news for households with animals: foamflower is regarded as non-toxic to pets and people. It appears on neither the ASPCA toxic plant list nor Cornell's poisonous plants database, so you can plant it in a shady bed without worrying about curious cats, dogs, or children.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Safe
Foamflower is safe around cats. It doesn't appear on the ASPCA toxic list or Cornell's poisonous plants database, so a curious nibble won't hurt.
Dogs Safe
No toxicity is documented for dogs. A dog that digs at the foliage or eats a leaf should be fine, though a big mouthful of any plant can briefly upset the stomach.
Horses Safe
There's no record of foamflower poisoning horses, and it carries no compounds known to harm them.
Rabbits Safe
Rabbits can graze the leaves without trouble. The plant holds no toxins, so a few nibbled rosettes are only a cosmetic loss.
Livestock Safe
Grazing animals such as cattle, goats, and sheep face no risk from this woodland ground cover.
Birds Safe
Foamflower poses no hazard to birds that peck at the leaves or flower spikes.
People Safe
The plant is regarded as non-toxic to people. It isn't grown to eat, but there's nothing here that will harm a child who tastes a leaf.
Varieties
Beyond the wild species, a handful of named selections are worth knowing, chosen mostly for cut-leaf foliage or a touch of pink in the bloom.
Oakleaf
Carries deeply lobed leaves cut like an oak's, which set it apart from the heart-shaped foliage of the species.
Montrose 13
A selection prized for flowers that come in tinged with pink rather than plain white.
Cygnet
A named selection grown for its distinctively cut, finely divided foliage.
How to propagate
Foamflower is easy to multiply, and dividing an established clump beats starting from seed for both speed and reliability.
DivisionEasy
Spring or early fall; benefits from being divided or transplanted at least every other year. · One growing season
Division is the easiest and most reliable way to make more foamflower. The plant spreads on its own by rhizomes and stolons, so in spring or early fall you can lift a clump and pull apart the rooted rosettes, each ready to grow into a new plant. The clumps actually do better for it, so divide or move them at least every other year, and a fresh division settles in within a single growing season.
SeedModerate
Sow in late winter to spring. · Multiple seasons to flowering size
Growing from seed takes patience. Sow from late winter into spring, but expect slow, uneven germination, and count on several seasons before the plants reach flowering size. Foamflower is also largely self-incompatible, so you need more than one plant cross-pollinating before any seed will set.
Myths
Foamflower needs full sun to bloom well.
This is a woodland plant at heart, happiest in part shade to full shade. It makes an excellent ground cover for heavy shade, the kind of spot where most flowering plants sulk.
Foamflower is toxic to cats and dogs.
It turns up on neither the ASPCA toxic plant list nor the Cornell University poisonous plants database. It is regarded as non-toxic, so it's a safe choice for a shady bed where pets roam.