Question of the Week – Number 1: June 25, 2020

“Why is my hibiscus plant dropping so many of its blooms? Very few are opening.”

I get this question very often via my newspaper columns, radio programs, from friends and I offer it here in e-gardens.

Actually, my answer pertains to several members of the hibiscus clan, most notably althaeas (roses-of-Sharon) and tropical hibiscuses.

These plants start setting their flower buds in late spring, while temperatures are still comparatively cool and conditions are reasonably moist. Then, when hot, dry weather arrives, they can’t hang onto all the buds they have set and they start aborting many of them just as a means of survival.

Thoughts that have crossed my mind…
• You don’t see this happening in early summers that are unusually cool and moist here in Texas. We had one like that six or eight years ago, and althaeas bloomed their hearts out. They never dropped a bud.

• You don’t see it happening nearly as often in the Upper Midwest as you do here in the much warmer and drier Southwest.

• With tropical hibiscus, you see it much more commonly with plants that we’re growing in pots than those that we have planted into our garden beds. Plants in pots tend to become rootbound. They dry out much more rapidly than plants that have more or less unlimited root room in garden beds.

• I do need to remind you that these plants’ flowers last only one or two days. Don’t be surprised to see them fold up and drop in relatively short order. That’s strictly genetic, and there’s nothing you can do to stop it.

So, what’s your solution to bud drop with the hibiscus clan? Keep your plants watered thoroughly. If you have tropical hibiscus in pots, be sure to repot them when they become rootbound, and move them to a spot where they’ll get shade in the afternoon. Try to moderate the swings in moisture.