Pruning hibiscus for newbies

Longtime GardenLine listeners may know all this stuff, but based on the number of questions I got about hibiscus pruning at last Saturday’s home and garden show, I realized it was time for a tip sheet on the topic. So, this is especially for transplants to the area and gardening newcomers.

Here’s the dilemma: Since we didn’t have much of a winter, most hibiscus in the ground and in pots are still very much alive. Some may even have been blooming since January. But if you are hesitant to prune these tropical beauties because all the blooms, don’t be. Prune them back right now.

I know what you’re saying … “But Randy, I’ll be pruning away all the booms!” But here is the simple fact: Hibiscus bloom on new wood, so by pruning now and at least two more times this year, you will generate lots of new growth and more new blooms.

There may be many opinions out there on exactly where and what to prune, but in the Houston area, hibiscus will grow like crazy if fed adequately. And they should be PRUNED MORE OFTEN THAN YOU THINK! How much? Never by more than a third, and I always try to do a quarter.

Now, there IS one precise thing to consider when pruning hibiscus … just don’t overthink it. Properly pruning a hibiscus limb can really help fill out the plant. You want to make the cut about ¼ inch above a leaf node. A node facing inward will stimulate growth up and inwards; a node facing outward will force the growth to be more outward. So, cut above inside nodes if you want a fuller plant, and cut near the outside nodes if you want it to be more upward and leggy.

And here’s my one warning, and it’s a big one: NEVER, EVER prune them down to the ground - you won’t see any blooms until August. After hard freezes, it’s sometimes necessary to cut them all the way to the roots because of all the dead wood. But don’t get the wrong idea may think, “But that’s gonna be all new wood, right?” It’s more complicated than that, and it has everything to with the proper development of those nodes. In cases where freeze-damaged branches need to be cut back to the ground, I usually recommend just buying new plants – they’re pretty cheap, and you’ll have blooms immediately.

Finally, feed them when you prune them! Hibiscus are cousins of the rose, and roses are the heaviest feeders of all. Three or four feedings in a year with hibiscus food is ideal - never do it just once. By the way, hibiscus foods are not designed as “super bloomers.” They are higher on nitrogen content than phosphorus. That’s because nitrogen promotes new green growth, and new growth equals new blooms! Also, plant them in rose soil, never potting soil. Treat them like the tropical woody perennials they are - with a soil that has more girth, rather than a light, fluffy potting soil.

Top 10 Rules for Pruning Hibiscus

  1. Don’t prune when it’s too hot or too cold. (Now is the perfect time.)
  2. Do it several times in a year; new wood equals new blooms
  3. Don’t prune a plant that appears stressed.
  4. Give ‘em a good watering the day before the pruning.
  5. Feed ‘em. They are heavy feeders like their cousin, the rose.
  6. Make sure your pruning shears are sharp.
  7. Never prune more than one third; one quarter is even better.
  8. Always prune away weak-looking inner growth.
  9. Top-dress containerized hibiscus with compost, not mulch.
  10. Deadhead spent bloom casings where you can to refocus energy.