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All About Hollyhock
Hollyhock falls under the genus Alcae which consists of over 80 different species in the mallow family Malvaceae. Hollyhock is native to Asia and Europe, and they can be annual, biennial, perennial.
A majority of hollyhocks tend to be biennial meaning their lifespan is 2 years. For those that are biennial, they spend the first year growing foliage and then they will bloom heavily the second year.
Hollyhocks have tall stems with small hairlike coverings on the stems. They feature flowers that are cup-shaped and come in blue, red, pink, purple, yellow, white, and even black on occasion. The leaves on Hollyhocks are coarse and palmate in shape.
They can grow 6 to 8 feet tall and approximately 1 to 2 feet wide once completely grown. It is crucial to keep this in mind when planting them in a garden.
Caring for Hollyhocks
When to Plant Hollyhocks
If you plan to plant hollyhocks in your garden, then it is best to plant the seeds in the summer months. This ensures that you are avoiding the last frost of the year in the spring as well as the first frost in the fall. You want to have a soil temperature of at least 50 degrees if you are planting hollyhock seeds in a garden instead of a pot.
You can plant hollyhock seeds in the spring if you are planting them in a pot under cover so you can protect them from any frost. The same applies if you plant the seeds in the fall as you can bring them indoors once the temperature drops significantly. Hollyhocks can be planted in USDA zones 3 through 8.
If you do plant your hollyhocks in a pot to begin, it is a good idea to transplant them to an outdoor garden once the weather is good. They have long taproots and transplanting them can be hard on the plant so the sooner you are able to do this, the better it will be for the plant in the long run.
When planting hollyhocks in the ground it is best to plant them approximately ¼” deep into the soil and 2 feet apart in order to give the plant plenty of room to grow.
Hollyhocks thrive in full sunlight. For the best results with a hollyhock, provide them with at least 6 hours of direct sunlight per day. They can have partial shade, but they will not do well if they are in full shade all day long.
If you have just planted hollyhock seeds, you will want to water the seeds daily for the first few weeks after planting. The soil should remain moist, but not overly soggy. After the hollyhocks have grown to full maturity, they can be quite drought resistant so you do not have to water nearly as frequently.
If you are not getting any rain to wet the soil, then you will want to water 2 to 3 times per week even after the blooming season to ensure that the new seeds are getting the proper hydration. If the area you live in gets a good amount of water from rain, then you can reduce your watering to 1 or 2 times per week.
Hollyhocks are fairly drought tolerant, but they do prefer a well draining soil if possible. A soil pH of 6.0 to 8.0 is ideal for a hollyhock and it is a good idea to have a soil test performed prior to planting hollyhock seeds.
If you need to raise the pH you can always add limestone to your soil or you can add sulfur to lower it. It will take time for these changes to take place so it is crucial to plan ahead and make changes prior to planting seeds.
Adding approximately 2 inches of compost into the soil before planting hollyhock seeds is also a great way to enrich your soil.
Hollyhocks are known to self-seed, meaning they will produce seeds and drop them so that if the plant dies off that year, the new seeds will begin to grow.
This can be frustrating for some if they do not want the plant to continue to grow into more plants the following years.
If you do not want your hollyhocks to self seed then you will want to pinch off the flower before it fades and grows a seed pod. Once the flower fades and turns brown, that means it has already created a seed pod and may have dropped seeds into the soil.
Are Hollyhocks Susceptible to Disease
Hollyhocks are fairly durable plants and are truly only susceptible to hollyhock rust. Hollyhock rust is caused by Puccinia heterospora, which is a fungus. It is easily noticeable as it shows up looking like yellow spots on the top of the leaves and rust pustules on the bottom of leaves.
The spots can grow together fairly easily and begin to take over the plant. You may notice leaves falling off and the disease spreading to the stems as well.
Hot and humid temperatures can cause hollyhock rust. The best way to treat it early is by removing any leaves that show signs of hollyhock rust and either burning them or discarding them immediately.
There are other things that can be done to prevent hollyhock rust from continuing or to prevent it from ever happening. These include only watering the soil and not the plant itself. If moisture sits on the leaves too long this can cause hollyhock rust.
If you are using a soaker hose, you can put it on a low level so that the water does not spray back up onto the plant. Some people also choose to use a spray bottle, which works great as well if you are just carefully spraying the soil. It is also important to water in earlier hours of the day so that the plant has plenty of time to dry out before the sun goes down.
It is also important to be sure that the plant has adequate air circulation so it does not have moisture just sitting. People will plant hollyhocks against a wall so just ensure that if they are against a wall, they are still getting adequate air to keep them dry.