Foam flower plants (Tiarella cordifolia) are perennial wildflowers native to the forests and woodlands of North America and Eastern Asia. Foam flowers form six to ten inch tall clumps of deeply veined heart shaped leaves that may have burgundy blotching. From late spring until early summer they produce small star shaped white flowers on wispy twelve inch plumes. In the winter the foliage turns a bright orange.
Foam flowers require partial shade to grow best. They will tolerate full sun or full shade as well. They grow in zones three to eight.
Foam flowers like moist, rich soil that is neutral or slightly acidic. They will not tolerate wet feet, but cannot dry out, either. The goal is to keep them moist but not soggy.
Foam flowers are propagated by division or seed. To grow from seed, plant the seeds in a soilless growing medium immediately after collection. Keep the soil about 70-75F for the thirty days it will take the seed to germinate. Plant in the fall. Prepare the soil by tilling to a depth of six inches, then covering the soil with three inches of compost. Till that into the soil completely. Dig a hole slightly bigger around and as deep as the root ball. Place the plant in the hole so that the top of the crown is slightly above the surface of the soil. Fill in the hole and firm the soil around the plant. Water in.
To propagate by division, dig up the clump of foam flowers and gently separate the plants, making sure each plant gets some roots. Plant as mentioned above. Foam flowers can go years without being divided and are generally low maintenance plants aside from their watering needs.
A third way to propagate foam flowers is to remove offsets from the stolons of the plant and root them. They must be placed in a mist chamber or in a plastic dome until rooted to keep them from drying out. As soon as they are rooted, remove them from the mist chamber so the roots do not rot. Plant as described above.
Foam flowers are astringent and are generally left alone by deer and rabbits. They do suffer from slugs, black vine weevils, foliar nematodes, and mealy bugs. Black vine weevils attack the crown and will eventually kill the foam flower if not treated for. A pesticide containing carbaryl will exterminate the pests. Slugs can be treated for with an iron based bait such as Sluggo or Escar-go that is spread around the plant. When slugs swallow it they stop feeding and starve. The iron based bait is not as poisonous to pets and children as the old copper based bait. Foliar nematodes should be avoided by buying only plants free of the pests. Mealy bugs can be treated by insecticidal soap. Be sure when treating them that you get the soap on the top and bottom of every leaf or the treatment will be ineffective.