Marshmallow
Althaea officinalis
Marshmallow is a flowering perennial that is related to the hollyhock. This plant gets up to 5' tall (1.5 m) and looks especially attractive in the back border of a garden. Marshmallow attracts bees and butterflies. The roots are very high in mucilage, a polysaccharide with gelatinous properties, which makes it perfect for making soothing herbal remedies or homemade marshmallow sweets. Marshmallow is easy to grow and can be grown along streams, marshy areas, areas with salt water, or in a garden bed. Hardy to USDA zones 3-9.
How to Grow Marshmallow
Quick Info
Put away the pen and paper
Plan your veggie garden in minutes with Planter's easy drag and drop planner.
Try Planter for Free
Related Articles
Diseases
Beneficial Critters
Growing from Seed
Marshmallow can be started indoors anytime, but it works out well to start them 6 weeks before your last frost date. The germination rate can be increased if you scarify the seeds before planting. Use sandpaper or (something else very rough) to scratch up the seed. Sow the seeds on the surface and barely cover them with rich soil. Lightly press them down. Keep the soil moist and warm until they germinate. You can direct seed in the garden in the fall through spring. Thin seedlings, one for every 2 feet (60 cm).
Planting Considerations
Marshmallow needs a lot of room to grow, both vertically and underground. It has a very big root system. The roots can be divided in the fall to create new plants. It can self-seed, but it won't take over your garden. Marshmallow isn't too picky about pH and can handle an area with a lot of clay soil. It grows best with cool, moist roots and sun on its leaves. It's possible to grow marshmallow in a container if it is deep and wide enough for the roots to grow. It's possible for Althea officinalis to cross-pollinate with other family members like hollyhocks and the common mallow, so plant away from these plants if that is a concern.
Feeding
Marshmallow doesn't usually require ongoing feeding as long as it has rich soil. Every spring you can add a good dose of compost to add nutrients and help keep the roots cool.
Harvesting
Leaves and flowers can be harvested every season. Roots should only be harvested after 2-3 years of growth to allow the plant to mature. You can use a garden fork to dig up the roots carefully. A hori hori gardening knife makes it easy to cut pieces of roots. The best practice is to harvest a portion of the roots every 2 years. Harvest up to 3/4s of the roots and replant the remaining root crown. If you wish, you can harvest the whole plant.
Storage
Scrub the roots clean. Marshmallow root can be used fresh or dried. Drying the root is the best for long-term storage. Chop up clean roots and dry them with a dehydrator for best success. Store the dried plant material in glass jars and put it somewhere dark and cool. Dried leaves and flowers are best used within 1-2 years. Roots may be stored for 3-4 years, but they are at their best before that time.
Pruning
No need to prune a marshmallow plant. You can cut down the dead foliage anytime in the fall or winter.
Herbal Use
Every part of marshmallow is considered edible. The flowers and leaves can be used in salads or as garnishments. The root has historically been eaten like a vegetable. In the herbal world, marshmallow is known for its mucilage and its ability to soothe sore throats, irritated digestive systems, and skin ailments. Marshmallows can be made from the root infusion. Marshmallow root is known to have anti-inflammatory properties. Due to the high mucilage content, marshmallow may affect the absorption of medications. Always consult with your healthcare professional before using herbs.
