Cultivating hollyhocks: Roses on stems
Hollyhocks are associated with romance and olden days. In this article, you can read how to grow the beautiful flowers.
In many of Hans Christian Andersen's fairy tales, hollyhocks were included as one of the flowers that could be found in almost any farming community. Its Latin name is alcea rosea and it originally comes from southwestern and central Asia but is also known from the Balkans and Greece. Today, you can find hollyhocks growing wild in nature. They have spread from the gardens. The botanical family name is the mallow family. The same family includes, for example, hibiscus, whose flowers in many ways can resemble those of the hollyhock.
Rose with a deep taproot
Most hollyhocks are biennial, meaning that when you sow a seed and the plant develops leaves the same year, but non or extremely rare flowers. Instead, the hollyhock uses its energy to develop a good root system. However, you don't have to wait two years every time there have been flowers. The plant usually sets new shoots from the base after the flowering shoots have withered away. Otherwise, the efforts of developing a taproot and a good root system would be wasted.
Biennial or annual
Annuals set flowers already in the first year but are not found in a nearly as large and beautiful a selection as the biennials. It is precisely the colours - and the very different colours - that make the hollyhock particularly popular, and it blooms for a long time, that is, from July and to October, constantly with new and fresh flowers on the up to three-meter-high stems. However, in the garden, you cannot be completely sure that the colour of the self-seeded neighbour plant is the same year after year. Especially bumblebees pollinate the hollyhocks, and when they fly from flower to flower and from one plant to another, pollination occurs and thus perhaps a different mix of colours. But that is precisely the charm.
Cannot be divided but can be planted
Perennials can be divided, but not hollyhocks. In a plant school, you can buy a finished plant that was sown the year before and where the root system is packed in the pot, but if you want to get started yourself, you have to sow. Here, you can take mature seeds from a hollyhock that has flowered. Typically, the first seeds will have matured in August when they have a brownish membrane around them. Each stem gives many seeds, which are collected in a round flat ball, so you probably will not have any problems getting permission to take a single roundel from a friend or neighbour.
How to sow
You can sow the seeds as soon as they are matured, just like the hollyhocks would do naturally. This means that you can sow them almost all year round, as long as you can get into the soil and ensure that it is not too wet. Although the taproot of a hollyhock likes to be in moist soil, the seeds should not be soaking in water. Therefore, March can be a good time to sow the seeds. Sow them a few centimetres deep in soil adapted for germinating seeds. The soil should be kept evenly moist and placed in a bright spot at around 20°C. After they have germinated and grown for a week, you can repot them. Keep them in a bright spot, and when the frost is over, you can plant them outside; that is approx. in May.
Where to place the plant
In older pictures, you often see hollyhocks placed under a canopy, especially in front of thatched houses without gutters. That was also an ideal place. The hollyhock likes to lean against something and to bask in the sun against a wall, but they definitely do not like dry soil. The roots should be in slightly moist soil at all times. So maybe it is not under your roof they should stand, but if you have a fence or a hedge, it could be the perfect solution. Of course, you can also put bamboo sticks in the ground to support the flower flower stem, but if they stand in reasonable shelter, they are actually quite strong and can, in most cases, hold themselves up. Although they need moist soil, they should not be in the shade but preferably have as much sun as possible. However, they can also tolerate partial shade.
Hollyhocks are very undemanding. They like to have compost, but otherwise, fertilization is not necessary. Pinch off the seed heads as they mature and remove withered flowers. If there has been a dry period, make sure to water the hollyhocks properly.
Hollyhocks are generally very healthy, but they can get rust, especially if they lack water. The rust appears as yellow to orange spots on the leaves, withered flowers, and brownish spots on the stems. Rust is a fungal disease called puccinia malvacearum, which can be difficult to control once it has set in. If you see yellow-orange spots on the leaves, you should remove them immediately. Rust can also be prevented by cutting the plant down when all the seeds have been harvested.
The hollyhock Alcea Officinalis grows wild in many places in Denmark and has pink flowers. Its height is slightly lower, namely 60-130 cm.
The garden hollyhock Alcea Rosea generally reaches around 180cm to 2 meters in height.
Here are examples of other great varieties:
- Alcea rosea var. Nigra 'Jet Black' is almost black or dark purple.
- Alcea rosea 'Polarstar' has white flowers with a yellow center.
- Alcea rosea 'Radiant Rose' produces pink flowers.
- Alcea rosea 'Pleniflora Apricot' has orange pink flowers.
Om Lars Lund
Danish horticulturist and journalist
Lars Lund has for many years engaged in the garden and greenhouse. Lars has published many books about greenhouses, and he has participated in many Danish horticultural TV shows. He is a walking garden encyclopaedia, and he has answers for most basic cultivation questions – also the more ambitious ones.
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