GROWING ADROMISCHUS, a beginner’s guide.
What are they?
Adromischus is Greek for “stout stem” and pronounced Adrommiskus. It is often abbreviated to “adro” (singular) and “adros” (plural). They mostly grow in the winter rainfall areas of South Africa and southern Namibia, although a few are also found in summer rainfall areas and even a few which may receive rain at any time. Summers are mostly hot and dry. In nature, even in winter they can endure periods of drought, so they can survive on moisture from fog, mist and morning dew. They grow on open plains, in and under cracks in rocks, in grit pans and on mountain tops. They are often found in the shade of bushes or over-hanging rocks.
Adromischus are highly succulent, leafy plants where the leaves grow spirally around them stem. They are grown for their attractively shaped and often patterned leaves, more than for their flowers which are mostly small and rather insignificant. Most of them will produce their tall flower spikes in summer a few will persist through autumn.
There are currently 29 species plus a few subspecies and varieties. They are grouped into 5 sections of related species. They are extremely variable in size, shape and markings.
How do I grow them?
As with most plants, Adromischus can have their problems in cultivation but are easy and rewarding to grow, if you take the time to learn and understand their needs.
In the spring and autumn with cool or cold nights and warmer days, they are actively and visibly growing, producing new leaves. During the longer days of and summer and cold, dark days of winter they prefer a “resting” or dryer period. So they need water while growing but little or none when resting.
Water well when you do but be sure to let them dry out between watering and if in doubt, don't water. They are succulent plants so survive drought better than being wet for too long. Use rainwater if you can. They prefer their growing medium and water to be just on the acid side of neutral.
When growing vigorously, Adromischus produce lots of new leaf growth which requires food and minerals. They do appreciate feeding but how much depends on what growing medium you use. If grown in a grit-soil mix or a commercial compost, they need less additional feed at first because it's already present in the mix. If it's inert like pumice then they will certainly need regular low nitrogen liquid fertiliser. Some growers advocate full strength feeding at the beginning and end of of the growing season, to give them an early boost and then to help them recover from the effort of flowering. In general I recommend half strength low-nitrogen liquid fertiliser on every watering in the main growth periods of spring and autumn.
A common mistake is watering the plants during the heat of summer. It's never an exact science, but generally when night time temperatures are never below 15C – 60F, adros shut down and won't take up any water. So the roots may rot and the plants collapse.
Where should I grow them?
Adromischus are quite tolerant and will grow in a greenhouse, on a windowsill or under artificial lighting. They will grow in whatever country you live in, be it in the Northern or Southern Hemisphere, as long as you stick to the spring-autumn growing regime and you can provide the conditions they need.
Adromishus need good light, especially when growing. If they are grown in natural light some sort of shading is often beneficial in summer. They can be damaged by scorch in a just a couple of hours if they get too hot, so air movement with a fan can help with cooling. In habitat they can tolerate freezing conditions for short periods in winter, but there it invariably warms up during the day. Elsewhere in cultivation, winters can remain cold for long periods so less water will be needed by the plants then. A minimum winter temperature of 3C - 37F will suffice. Anything over 32C - 89F in summer can cause damage, especially with no air movement.
If you have no natural daylight and want to grow them, LED lighting is the way to go, but that's a whole different game of which I have no experience. However, in theory, it should be very successful as both light and temperature can be controlled to provide the necessary conditions and you may even be able to extend their growing periods.
What do I grow them in?
Growing medium, soil, compost, substrate......all terms for what Adromischus can be grown in. What they grow in best is often the topic of much opinion and debate. Some growers will only use a mineral blend, others prefer a soil and grit mixture. It really depends on what you can find and buy locally or get delivered. Essentially the growing medium just needs to hold water for a short period before drying out, so needs to drain well and not stay wet for days. It's interesting to experiment and see what works best for you and your individual growing conditions.
Most people find standard plastic pots are fine but others prefer ceramic or even fancy ornamental ones. Again it doesn't really matter as long as the container drains freely and the basic growing principles are followed. Whatever type of pot you choose need not be large. I grow my plants in 5cm (2 inch) plastic pots to start with, then only pot on to something larger as required. In nature Adromischus often grow in very root-restricted places.
Where can I get them?
It's great to visit a nursery to choose plants, but most people buy their Adromischus online these days. This can be risky, as due to their ever-increasing popularity, prices have increased, supply is limited and many sellers are only in it for a quick profit, selling poor quality and often wrongly-named plants. So do some research before buying. Perhaps join one or two Facebook `groups` to see where others are buying and ask for advice. Find recommended sellers.
How do I propagate them?
These plants in most cases will grow quickly and easily from leaves. They can be carefully removed from the stems and will produce roots from the heel of the leaf. Some growers plant them immediately into trays or around the sides of pots. Some will leave them on the surface, others will bury the heel. I prefer to leave them in air until roots appear, before planting them. Either way they shouldn't be watered until they have roots, so have some means of using that water. I plant them into the pot they will grow in for year or more to save transplanting and root disturbance. After a period, which may vary from weeks to many months, new leaves will grow from the base of the leaf and they can be grown on as adult plants. It's also possible to take and root stem cuttings from taller growing species and root them in a similar way.
Collectors often refer to different “clones”. A plant grown from a leaf or stem would be the same clone as the plant it was taken from.
Many growers advocate removing a few leaves as soon as possible for “insurance” plants, in case the mother plan dies. It's also useful to have spares to experiment with in different conditions (growing medium, location, etc.) to see what does best in your particular environment. Growing a few spares from leaves will also give you material to share or trade with other growers to increase your collection.
Can I grow them from seed?
Certainly, but seeds are rarely commercially available. Many growers with the skills and ideal conditions will produce their own seeds by carefully cross-pollinating different plants. Due to the tremendous popularity of Adromischus now there are many hybrids being grown by seeds produced by specialist growers.
But assuming you have obtained good seeds, you need to understand a few basics for success. Once again there are many opinions and methods of how best to proceed. Some growers sow in autumn but others have success sowing in spring, so both will work.
The seeds are small, so treat them carefully. The same growing medium you use for plants can be used to sow seeds, although some growers prefer to sieve out the mix of larger particles. Some advocate sterilizing soil before sowing but others consider it detrimental. I know many successful growers who microwave the sowing medium on high for 5-10 minutes before sowing, once it has cooled of course.
A variable temperature range of 15-20C (60-70F) during the day to 5-10C (40-50F) at night works well for germination as it mimics what they experience in habitat. Small pots or trays may be used. Sow the seeds evenly and gently water them from above or let the pots or trays stand in water until the surface is wet. Some growers sow onto a shallow top layer of fine grit. Fine sand is not recommended as it can harden or “cake” when it dries out. If sown onto fine grit, the seeds should be carefully washed down between the particles. This is my preferred method as the grit supports the seedlings as they grow and also inhibits any growth of moss or algae on the surface. The pots and trays will benefit from being covered by either clear plastic or glass, to maintain the humidity. They can also be put inside plastic bags. Whatever is used should then be shaded from the sun. Under the right conditions healthy seeds will usually germinate within a week to ten days. Any cover should then be removed otherwise the tiny green seedlings can rot. They appreciate air moving over them with a small fan and should be kept out of direct sunlight for the first few months.
Keep them growing by lightly watering all the way through their first year. They should be kept moist (but never wet for long periods) and as they increase in size can dry out for a day or so between watering. After this they should be large enough to be treated as adults.
What about bugs and other nasties?
Cultivated Adromischus can suffer from mealy bugs both above and below soil level, but most generally available pesticides will control them. A more persistent pest is Western Flower Thrips. They will feed on new leaf growth and are not at all easy to kill. Acephate is a good systemic pesticide which controls thrips but is not available in many countries due to its extreme toxicity.
Seedlings may be attacked by Sciara flies, also known as mushroom flies or fungus gnats. They lay their eggs in the soil and the larvae eat the seedlings. A general systemic insecticide, especially Imidacloprid, will usually control them. Another problem for very young seedlings is damping off. This is a fungal disease that usually occurs when the soil is too wet and there is not enough air moving over the seedlings which first turn white, then opaque, then die. It can be controlled by using a solution of copper sulphate.
Other fungal problems may effect adros. As previously mentioned, they can rot from below but also rot from the base of a flower stem. This then travels down into the plant and within a very short time it is beyond saving. Another reason to have those “insurance” plants. Other pests and animals which can cause serious damage are slugs, snails, caterpillars, crickets, birds and mice. All of them can appear suddenly and unexpectedly, so need to be considered and kept away at all costs.
I'm ready to give them a go. Any last words of advice?
It's all about experimenting and seeing what works best for you in your conditions.
Remember that all this advice is guidance. Every grower has a different environment and conditions and this will affect how their plants grow, so it's a process, a learning curve.
Everyone has successes and failures along the way, but every success is a joy and assuming you discover why, every failure should help to understand more about these plants and how you can grow them better.
There is so much more to learn about these fascinating plants.
For more information I would suggest you download our Adromischus Handbook (it's free!). The link can be found in the “Books & articles .pdf files to download” album of this website.
For more advice and another opinion, you should also look at the comprehensive and specialist website of my friend, Derek Tribble, “Adromischus Displayed”.
Download the Adromischus handbook to your computer;