|
March is a busy month for the Sun Coast hibiscus gardener – for any kind of gardener for that matter. It is cool enough to be comfortable in the garden and since rain usually isn’t much of a factor, not many gardening days will be lost due to that act of nature. Many plants have been dormant or nearly so during the previous several months and March brings their awakening.
We rationalized in the February section that we were going to, if anything, err on the safe side and approach the subject of pruning as though all our readers lived close to I75. With that guideline in mind, March is the month we remove cold-damaged limbs (if any) at least down to live wood and generally shape the plant for the long growing season ahead. See The Hibiscus Handbook for a rather detailed description of the "do’s and don’t" of pruning, complete with a few illustrative drawings.
If you have been thinking about moving in-ground hibiscus, this is the time to do it. They are semi-dormant now and are less prone to suffer severe shock than if you wait a month or so. Of course, prune the plant to compensate for the roots you will cut in the moving process. The rule of thumb is to water transplants daily for 10 days to 2 weeks, however, the weather and your local soil conditions will play a role in this exercise. While transplanted hibiscus must not dry out, they will suffer from over-watering just like any hibiscus. Furthermore, since the pruning process removes many, if not most, of the leaves, which reduces transpiration, the plants will require less water. Covering the transplant with a piece of burlap or an old sheet for four or five days will help reduce leaf loss.
March is a good time to mulch your hibiscus (and everything else) before it gets any warmer. Correct that to, "before it gets any hotter". If you haven’t been mulching all your plants, both in-ground and in pots, this would be a good time to start. The decrease in the amount of watering required is amazing. If you haven’t climbed on the water conservation wagon, you may find the decrease in the amount of time necessary to water your plants appealing. We have found that mulch may cut the number of waterings necessary in half.
Going hand-in-hand with the pruning process is the staking or re-staking of your larger (or less sturdy) hibiscus (in pots and in the ground too). If you use wood stakes, don’t assume last year’s stakes are still able to support the plant. Wiggle the stake a bit and you’ll find, it’s even money it will be rotted off and will need to be replaced.
Also to be considered as pruning takes place, is the need to repot or repot-up your potted plants. If your potted plants have been in the same pot two years or more they are most likely candidates for either repotting or potting-up, because they are probably root bound. To define our terminology, "repotting" involves both above and below ground pruning and replacing the plant in the same size pot, while "repotting-up" or "potting-up" involves moving the plant to a larger pot with limb pruning and disturbing the root ball.
When potting-up, it is recommended that you increase the pot size only to the next larger size, whatever that might be since, as you can imagine, the number of times potting-up can take place is limited by the size pot you want to manhandle from place to place. Use only new potting mix and rough up the root ball with some abandon, or score the root ball with a knife, as you move the plant from the old to the larger pot.
Repotting involves taking the plant out of the pot and using a really big knife or a sharp hatchet to cut away least a third of the roots, including a portion of the swirling root mass that has probably formed at the bottom of the root ball. Put what’s left in the same pot, using only new potting mix to replace what you have cut away. While you may use the same pot or another one the same size, it’s always best to clean them up with a 10% bleach solution. If you are repotting a number of plants at the same time and you have a big bucket, submerging the clean pots in the bleach solution really works well.
If about a third of the roots are cut away while repotting, then about a third of the limbs should be removed from the above ground plant. The major pruning of limbs most members conduct at this time of year will, in most cases, be more than a third and will therefore be more than sufficient to compensate for the roots the plants lose during the repotting (or potting-up) process. Of course, it is much easier to do either of the potting processes after the plant is pruned.
After pruning, repotting or potting-up, thoroughly drench the plant and thereafter provide only modest water. As is the case with in-ground plants, after pruning most of the leaves are gone which dramatically reduces transpiration and the need for water. So cut back the water without letting them go bone-dry, thereby avoiding damage to the root system.
Hibiscus do not have many fungus problems, but a thorough spraying with Funginex or something similar after pruning is recommended.
Don’t fertilize right after pruning. Some say to wait a week or so before fertilizing. Others say to wait until the first full leaves appear. We have tried both approaches as well as fertilizing right after pruning. Although the "tests" were on a relatively small number of plants, we can’t say we see any great difference in the results.
One more item related to pruning. The result of any pruning is a quantity of cuttings which can be grafted if appropriate (if root stock is available) or rooted. If you have root stock, but grafting is a mystery to you, see The Hibiscus Handbook for details. Curt Sinclair says that many of the hibiscus varieties that once were thought to propagate only by grafting will grow on their own root. That thought makes it fun to try to root every cutting that results from your pruning, garden variety or not. Nothing ventured, nothing gained. (We think Curt mentioned that Red Snapper will not root.) So what do you do when 90% of your cuttings root? May we suggest planting them in small pots and using them as gifts or – contribute them to the gift table at our Show in September. Need we remind you to track the names of the cuttings, from the time they are cut to their first blooms? This is no small issue when you are pruning many plants.
While we have expended considerable space about pruning and related subjects, we must hasten to state that pruning, particularly severe pruning, is not mandatory for plant health and bloom production.
In ground hibiscus, not injured by cold weather, may virtually never need pruning – if they are good neighbors in the garden community where they live (i.e. they aren’t bothering other plants – or you) and they continue to flourish.
Plants in pots, however, will require pruning at some point in their life. When that time is will depend on a number of factors. A major factor relates to the size pot the plant is in. But whatever the pot size, there will be a time when the plant is so large that it will tip over with the slightest breeze. Some build mechanical structures to secure pots in an upright position, which sounds like a lot of work. Probably sometime after the tipping business begins, once a day watering leaves plants with limp leaves – everything else being equal - a pretty good sign of a root bound plant. A root bound plant needs relief of some type – “potting-up” into a larger pot (which will probably call for some branch pruning) or repotting in the same size pot (which will require a balanced pruning of roots and branches).
February April
|
