Milkplant is by no means the same as milkweed: There are around 200 different species and numerous varieties, all of which have very different requirements in terms of location and care - especially since only a few species are hardy in our latitudes. As a rule, they are grown in containers so that you can enjoy the magnificent plants for a long time. When purchasing, be sure to pay attention to the correct species name so that you can supply it correctly.
What is milkweed and where does it come from?
The milkweed is a genus of around 200 species that produce magnificent flowers in various colors. It is native to North and South America and belongs to the dogpoison family. Milkweed plants are valuable pastures for bees and butterflies, but require different location conditions and care.
Origin and distribution
The milkweed genus includes around 200 different species, most of which are native to the New World - i.e. North and South America. Some varieties also occur in southern Africa between Tanzania / Zimbabwe and South Africa. Some species - such as the common milkweed - now grow as neophytes in many other areas of the world. The genus is assigned to the dogpoison family (bot. Apocynaceae).
Appearance and growth
Most milkweeds are perennial, herbaceous plants. Only a few species are only annual. Depending on the species, Asclepias plants reach heights of between 70 centimeters and two meters. The strong rhizomes from which the plants form numerous runners are also typical. When planted out in the garden, they quickly overgrow larger areas, which is why you should definitely install a root barrier when planting.
leaves
Visually, the short-stemmed leaves, but up to 17 centimeters long, are somewhat reminiscent of rubber tree leaves. They are typically elliptical to elongated in shape and, in most species, have downy hair.
Flowers and flowering time
The mostly multi-flowered umbels appear between June and August and shine in strong colors such as pink or orange. Pollination is carried out by insects, especially bees and butterflies, especially since milkweed plants are valuable pastures for bees and butterflies.
Fruits
Two spindle-shaped follicles develop per fertilized flower, which usually stand together like two horns. These are densely packed with numerous flat seeds, which in turn are covered with silky hairs up to four centimeters long. The hairiness, known by botanists as coma, is used to spread the seeds by wind, and the milkweed plants also owe their species name to it.
Toxicity
Like all dogweed plants, milkweed plants are poisonous to both humans and animals. The escaping milky juice can also cause skin irritation.
Which location is suitable?
Silk plants prefer to be in full sun, although some species also thrive in light partial shade. It is best to place specimens grown in pots outside during the summer, but you should slowly get used to the stronger sunlight. The large space requirement is also important: Since the perennials can grow quite tall and also multiply diligently via underground root runners, you should plan a planting distance of at least 50 centimeters when planting in beds. Potted plants need an appropriately wide pot.
Substrate
Milk plants planted in the garden thrive in humus-rich, well-drained soil with a low clay content. The perennials will grow better if you mix some compost into the excavated soil when planting. A humus-based pot plant substrate (€18.00 at Amazon) is suitable for potted plants, which you can make more permeable with perlite or expanded clay. Good pot drainage should not be missing to avoid waterlogging. To do this, the planter needs a drainage hole at the bottom of the pot, and you also fill in a drainage layer made of coarse, inorganic material such as gravel or shards of pottery as the bottom layer.
Planting and repotting
Species of milkweed that are not or only partially hardy should, if possible, only be cultivated in pots. In this way, overwintering is no longer a problem - unless you only want to care for the plants once a year anyway. Repot container specimens into a larger container and/or into fresh substrate approximately every two to three years.
The only plants that should be planted in the garden are hardy varieties or specimens that you dig up before the first frost and then overwinter frost-free. The winter-hardy milkweed plants in particular need a lot of space in the garden, but can be easily prevented from uncontrolled growth with a root barrier.
To make it easier for the plants to root, place them with the bare root ball in a bucket of fresh water before planting/potting. As soon as no more air bubbles appear, the plant is ready to be planted.
Watering and fertilizing
For he althy growth, milkweed plants depend on an adequate supply of water and nutrients, which is why you should water and fertilize regularly, especially those grown in pots. Always keep the substrate slightly moist during the summer months, but avoid excessive moisture - this can lead to rot. Excess irrigation water must not remain in the saucer either, but must be removed promptly.
Milk plants planted in the garden need protection from moisture in winter, but in summer a layer of mulch protects them from drying out. Fertilize the plants about every two weeks between April and September with a liquid container plant fertilizer. Hardy garden specimens, on the other hand, enjoy plenty of compost in April, June and at the beginning of autumn.
Cut milkweed correctly
Regular cutting of milkweed plants makes sense for better branching and therefore bushier growth and more lush flowering, especially since this prevents baldness in the perennial species. To ensure longer flowering, dead flowers should also be cleaned out regularly. Furthermore, the plants that tolerate pruning can be cut back to a height of around 20 to 25 centimeters before being moved to their winter quarters, thus taking up less space. They sprout again in spring.
Propagate milkweed
Silk plants can be propagated very well by sowing, proceeding as follows:
- Advancement possible from January / February
- sow on seed soil or cocohum
- do not cover as light germinates
- place bright, but not directly sunny
- Seeds germinate at 21 to 24 °C
- Always keep the substrate slightly moist and do not allow it to dry out!
- Germination time between three and six weeks
- detiping after pricking
The young plants can finally go outdoors from the end of May when the risk of night frosts has been averted.
Older specimens can also be propagated by division after flowering. To do this, dig them up including the rhizome and divide them with the help of a sharp knife. Then reinsert the individual pieces separately.
Wintering
Even if milkweed plants are often touted as hardy, most species are not, or only to a limited extent. These varieties die above ground over the winter months, but usually sprout again from the underground rhizomes in spring. To prevent them from freezing when there is frost, you should cover the root area with brushwood in autumn. It is also important that the plant is protected from moisture during the cold season.
Non-hardy species or specimens cultivated in pots, on the other hand, can be hibernated brightly and frost-free, but in a cool place at around ten to 14 °C. Bring them into their winter quarters in autumn as soon as the temperatures consistently fall below ten degrees Celsius. Water the plants little in winter and do not fertilize them. In spring, temperatures of less than 12 °C or late frosts can be problematic: These delay new growth or cause the plant to shed its leaves. Then the flowering starts later.
Hardy milkweed plants
Only the types of milkweed listed below are sufficiently hardy and suitable for planting in the garden:
- Asclepias amplexicaulis: needs dry, sandy substrate, growth height up to approx. one meter
- Asclepias ex altata: growth height up to about one and a half meters
- Asclepias fascicularis: adaptable species, occurs in mountains up to 2100 meters above sea level, lavender to pink flowers
- Asclepias hirtella: very adaptable, thrives on both dry and fresh soils, growth height up to approx. 100 centimeters
- Asclepias incarnata: swamp milkweed, growth height up to 150 centimeters
- Asclepias lanuginosa: Woolly milkweed, native to Canada
- Asclepias quadrifolia: commonly found on mountain slopes in North America
However, these species also depend on a favorable, protected location and light sun protection - such as a generous cover with spruce branches.
Diseases and pests
Diseases rarely occur in milkweed plants; only root rot caused by excessive moisture can be problematic. If in doubt, it is better to water potted plants too little rather than too much. Furthermore, the different species are susceptible to whitefly infestation. Aphids also like to settle on the large leaves.
Tip
If the leaves turn yellow in winter quarters, the plant is probably too warm. Temperatures of more than 12 °C during the winter break weaken the crop and lead to disease.
Species and varieties
Of the numerous types of milkweed plants, these are the ones we cultivate:
Indian milkweed (bot. Asclepias curassavica)
This species, also known as Curaçao silk plant or silk flower, is not hardy and can therefore only be cultivated as a pot plant or as an annual in the garden. Between June and August, the species, which grows up to 100 centimeters high, delights with red-orange flower umbels.
Common milkweed (bot. Asclepias syriaca)
The common milkweed is also known as the parrot tree or parrot plant. because their unripe fruits are vaguely reminiscent of a budgie. The hardy species is suitable for outdoor cultivation, but can also be cultivated in a container. The plant reaches heights of up to 200 meters, has large leaves and blooms from June to August in numerous pink umbels. The perennial, which is still rarely found in ornamental gardens, is a valuable bee food plant.
Swamp milkweed (bot. Asclepias incarnata)
The swamp milkweed also magically attracts bees and butterflies. The species thrives in sunny to partially shaded locations on moist to swampy substrates. It is particularly suitable for planting on the banks of garden ponds or other ornamental bodies of water.
tuberous milkweed (bot. Asclepias tuberosa)
The species, which blooms with striking orange flower umbels - which is why it is sometimes called orange milkweed - prefers stony, dry substrates and sunny locations. The species, which is popular in ornamental gardens, is only partially hardy in this country and always needs light winter protection. However, it is also suitable for pot cultivation, but must then be protected from frost over the winter.
