Common Mallow (Malva sylvestris) is from Europe, Britain, and Asia. It has been introduced to North American and South America as well as Australia. Mallow is a herbaceous plant that can grow up to four feet tall. The leaves are toothed. The flowers are large, rosy-purple with darker veins and five petals. Mallow blooms from the spring to the late summer. The leaves are used as a vegetable and the flowers for gargling and mouthwash. Common mallow is hardy in zones five to eight.
It is best to start your mallow from seed indoors or buy a plant at the local nursery. You can direct sow mallows in the fall, too. Mallows grow best in well-drained, loamy soil. To prepare your soil for mallows, till it to depth of twelve inches. Cover the tilled area with three inches of compost. Till the compost into the soil until they are well mixed. The added organic matter will make your soil drain well and add nutrients to the soil.
Mallow plants should be planted after all danger of frost is past. When you plant them, put some slow release fertilizer for blooming plants in the hole with the plant. This will give them more nutrients, too. Mallows will benefit from water soluble fertilizer every two or three months during the growing season.
If you are growing mallows from seed and want to get a jump at the season, you can plant them indoors eight weeks before the last freeze in your area. When the danger of frost ends, plant your mallows just as if you had bought small plants.
Mallows need to be watered every week in the growing season and once a month when dormant. They need one inch of water at every watering, as this makes the roots grow deeper. The best way to know how long it takes your watering system to put out an inch of water is to use several tuna fish cans. Set them near your plants and run the irrigation system until the cans have one inch of water in them. Run your irrigation system for that length of time each time you water your mallows.
Mallows don’t have many insect pests that bother them. Japanese beetles will sometimes chew on the leaves of the plant. Mallows are susceptible to several fungal diseases, including one called mallow rust. Mallow rust causes dark blisters on the underside of the leaves. It can kill the entire plant. It can also spread to your other mallows. As soon as you detect this disease, pull up the plant and put it in the trash. Do not compost that plant because it will just spread the mallow rust when you use the compost.
In the autumn, shear your mallow down to the ground for the winter. If you live in a cold climate, put mulch over the stumps to protect them from the weather. When it starts to warm up and plants start coming out of dormancy, remove the mulch so the mallow will start growing again.