Hollyhock mallow grows quickly, producing flowers in the first summer season after seeds are planted in the early spring or previous fall. For many gardeners, virtually no maintenance will be needed. At most, you may need to stake up flowers to prevent toppling from strong winds or apply a fungicidal powder if disfiguring fungal leaf spots bother you.
Light
In temperate regions, it’s best to position your hollyhock mallow in a full sun position. If you live somewhere that experiences intense afternoon sun, a partial shade location would likely be better to prevent leaf discoloration and promote better flowering.
Soil
Hollyhock mallow can tolerate a wide variety of well-drained soil types. Its preference is moist loamy or sandy soil that is reasonably fertile. But if the soil is overly rich, it can result in the flower stems sagging.
Water
This plant, once established, is moderately drought-tolerant. It prefers to be kept consistently moist but won’t survive in waterlogged soils.
Temperature and Humidity
Hollyhock mallow enjoys temperate climates of zones 4 to 7 and can handle light frosts during the transition seasons. Excessively hot and dry conditions result in the foliage turning from green to a scorched yellow. High humidity climates often see problems with leaf fungal diseases.
Fertilizer
Your hollyhock mallow will accept a monthly application of a balanced fertilizer during its flowering period, but it requires almost no feeding if the soil is moderately fertile. Avoid excessive feeding, as this can make the plant excessively leggy and cause it to sag.
Types of Hollyhock Mallow
By far the most popular variety of this plant is Malva alcea var. fastigiata sometimes known simply as “mallow” or “fastigiate hollyhock mallow.” It is a narrower, neater plant than the pure species, with larger saucer-shaped pink flowers.
Similar Species
There are also other types of Malva species that are sometimes confused with M. alcea. For example:
Malva sylvestris, including the popular “Zebrina’ cultivar, is a very similar plant to M. alcea, but its soft pink flowers are marked with striking purple veins.Malva moschata (musk mallow) is very close to M. alcea, but it is suitable for colder climates. Be careful about cultivating this species, as it is regarded as invasive in some regions. It is a shorter-lived plant, often considered biennial.
Pruning
Pruning of your hollyhock mallow is recommended to prevent this readily self-seeding plant from taking over your garden. For this reason, as soon as the blooms are spent, they should be deadheaded. This can sometimes also encourage a second flush of blooms in the late summer. Cutting the entire plant back down to the basal foliage is also an option after the bloom period concludes in the late summer or fall. Be aware that some self-seeding might occur using this method. If you want to keep your hollyhock mallow neat and compact, it’s worth pinching back new growth tips as they first appear in the spring. Be wary of adding hollyhock mallow clippings to a compost bin, as the seeds may persist and cause unwelcome volunteers when the mulch is used in the garden.
Propagating Hollyhock Mallow
New hollyhock mallow plants can be easily grown from healthy basal cuttings (cuttings taken from around the base of the plant) in the spring or early summer. However, this plant is so easy to grow from seeds that collecting seeds for replanting is a much more common method of propagation. If you do want to try vegetative propagation, here’s how to do it:
How to Grow Hollyhock Mallow From Seed
Hollyhock mallows are extremely easy to grow from seeds purchased from online retailers specializing in wildflowers or collected from the dried seed pods on existing plants. There is usually no need to start seeds indoors. The normal outdoor planting time is spring as soon as the soil can be worked, but even seeds planted in fall will usually sprout in the spring. Plant the seeds shallow, barely covering them with soil. Germination and sprouting are usually evident within two weeks.
Overwintering
When cold weather kills the foliage, cut the stalks down to the basal leaves. (You can leave a few plants standing if you wish for them to self-seed in the garden.) In borderline climate zones, (northern range of zone 4), cover the plants with a layer of mulch or leaves for the winter to protect the roots. This mulch layer should be removed promptly in the spring to prevent root rot.
Common Pests & Plant Diseases
There are no life-threatening pests and diseases for this plant, though Japanese beetles will often feed on them in regions where this insect is prevalent. In hot, humid climates, the plants can be susceptible to several fungal leaf diseases. While unattractive, these diseases are rarely fatal; if necessary, they can be treated with fungicide powders or sprays.
How to Get Hollyhock Mallow to Bloom
Hollyhock mallow rarely needs help to bloom, but deadheading spent flowers will encourage additional blooms. A plant that fails to flower at all is probably not getting enough sunlight.
Common Problems With Hollyhock Mallow
Hollyhock mallow is typically easy to grow, and the problems that do occur are cosmetic rather than life-threatening. Some common issues include:
Excessive Self-Seeding
Their ability to readily self-seed can prove to be an annoyance for some gardeners as volunteer seedlings can be tricky to remove once they are established. Careful deadheading and cutting back will be required during the summer if you want to prevent spreading.
Toppling Plants
With its tall, upright form, this plant may require staking in exposed windy locations or if growing in rich soils that cause legginess. Selecting a sheltered position out of strong winds is recommended.
