There are some varieties of desert rose that don’t require much pruning, while others need some to promote a bushier habit, or you may need to trim off any damaged parts. If you do any pruning, you can always use the pieces you have cut off as grafts or cuttings.
At the site of where leaves used to grow are ‘eyes’; this is where you would get new shoot from if this plant was pruned higher up the stem. Occasionally, insects will damage the growing tips, which then encourages the plant to throw out more new shoots further down the stem.
White Crispum is a very slow growing variety of desert rose that requires little to no pruning.
Whether you prune your plants for shape, to promote more flowers, or for another reason, don’t be afraid that this will kill your desert rose. They respond very well to extreme pruning, throwing out many new shoots, which will give you lots of flowers.
Sometimes you may need to do some root pruning. The reasons for this will vary, but always remember to use good hygiene and allow the wound to air-dry before re-potting. Seedlings often get pruned by caterpillars chewing off the growing tip. This can promote a bushier plant quite quickly.
If good drainage and hygiene is provided, there is far less opportunity for root rot to happen to start with. By good hygiene, I mean care being taken when re-potting and/or pruning, not recycling potting mix from a plant that has died (as that may be the source of a disease), and pruning any damaged roots with sterile utensils, allowing the plant to air-dry before it is re-potted. Simple steps, but important ones to help you maximise the best results for your desert rose.
Sunburn can occur when a large part of the upper branches has been pruned, resulting in the trunk becoming yellow/ brown; due to excessively high temperatures (heatwaves); or from a more sensitive variety (variegated) looking bleached or burned.
Once you have managed to successfully graft, you also need to be on the lookout for any problems that may arise with over-growth. This can happen right at the graft site or further down, towards the caudex.
When you prune a desert rose, the plant immediately grows new shoots all along the branches and caudex; this creates a bushier plant with lots of flowers. We don’t need this growth when we have just grafted a plant, as the rootstock will be inclined to reject the graft. You will need to remove any growth from below the graft to give the plant the best opportunity to knit.
The challenge here is not to wait too long to begin pruning. If you delay until after the new growth has begun flushing out, it will weaken the plants and set back their spring push. You will be cutting off canes that are full of new sap rushing to force the first leaves and flowers so keep an eye on the weather.
Don’t worry! In time you will develop a feel for this “sweetspot” between spring flush and last frost.
The following plant parts should be removed throughout the year as soon as they are noticed:
Suckers are shoots that develop from the base of the plant and are usually very vigorous. These suckers will have a smaller leaf, less glossy and a lighter green color. Every so often, if you are not on top of things you will see this light green stalk shooting directly up through the shrub and extending high above the plant.
These shoots are growing from the rootstalk of the plant. Remember my discussion of the grafting of the desirable rose onto a stronger rootstalk? Well, every so often a bud from this rootstalk will decide to grow. It will originate at or just below the soil line.
This shoot will grow like crazy and rob the plant of energy that should be going into developing new stems and flowers. Theses suckers will eventually flower, if you let them, but the flower will be very different and nothing too showy, probably white and small with only a few petals.
For these reasons, I suggest that remove these suckers as soon as they appear. With close inspection of the lower trunk of the plant you can see the graft point where most of the desirable canes originate, anything growing from below that needs to go.
Make sure to cut them as flush with the main trunk as possible. If you leave a stub of the sucker, additional suckers will develop on the stub so make sure to remove it all.
All dead wood, from large canes to small stems, should be removed when found. If you have pruned your plants every spring like you should, it is likely that you won’t find much dead wood. About the only time I encounter dead wood is when I’m pruning a shrub that has been neglected for several years.
These I call “project plants” and they can take a few years to reshape and re-invigorate. You will find that deadwood is much harder and more difficult to remove than the fresh young canes. You will probably need your loppers or even a small hand pruning saw to cut through the dead wood.
Simply cut it out and dispose of it. Diseased Wood As with dead wood, you should remove diseased canes as soon as they appear. Be careful to distinguish diseased canes from diseased foliage. If the disease is still in the leaf then there is no reason to remove the entire cane.
You can treat Foliage disease with other methods. If a disease has advanced to the point where it has infected the stems, it should be removed manually with pruning tools. Diseased wood is generally black or brown. When you cut into it, the inside of the cane will be brown. Healthy wood will be light green inside.
There are two important points to remember:
First, when you remove diseased wood, make sure that you cut below the diseased area so that all of it is removed. You can tell by looking closely at the piece you have cut to see if the cane looks fresh and green inside. If you see any black or brown streaks, you will need to cut again but lower down the cane until you can’t see any more discolored wood.
The other point to remember is that once you have made a cut into diseased wood your clippers are now contaminated and each subsequent cut you will be spreading the disease. I suggest you have a small cup of bleach diluted about 10/90 with water. Dip your clipper blade into it after each cut.
This may sound like a lot of extra work but when you are removing diseased wood it is critical. Luckily, most rose diseases don’t make it into the cane before they are dealt with so this usually is not a big issue if you are on top of things.