Tropical hibiscus lacking blooms after winter storage

I bring in my tropical hibiscus every fall and store it in my basement by the window. It remains dormant over the winter and I bring it out in May. When the plants were first purchased it was blooming profusely with constant blooms. It is now full of thick healthy looking leaves but it barely blooms. I May get 1-3 flowers a week. I fertilizer every 3 weeks. Why is this?

Thought #1: Look at your fertilizer label and make sure the middle number is the biggest. If you are using a fertilizer not specifically for flowers, that may be the problem.

Thought #2: How much sunshine do they get. They should be getting at minimum 6+ hours a day of direct sun - the more the better.

NOO, please! Hibiscus doesn't like too much N, and particularly doesn't like much P at all. Fertilizers with NPK RATIOS of 3:1:3 or 2:1:3 are very good. They REALLY like K, so the K content should be equal to or even slightly more than the N content. That plants can or will benefit from overdoses of P is a myth. Most plants use about 6X as much N as P, and about 3/5 as much K as N. Hibiscus wants more K than that and less P. Anything in excess of what the plant can/will use can be as limiting as a deficiency. Excesses of P cause Hibiscus blooms to abort and additional issues - particularly chlorotic foliage and antagonistic deficiencies of Fe and K.

If grown in pots, you should root prune and repot yearly. They have very vigorous root systems, and tight roots cause a poodle look because all the foliage tends to be concentrated at branch ends near apices (the growing tips of branches). Several stress factors can cause buds to abort. Tight roots, uneven watering (too much or too little), high root temps, inappropriate fertilizer, apids and bud/gall midges are all potential causes of aborted buds.

An excellent fertilizer regimen is Foliage-Pro 9-3-6 (a 3:1:2 RATIO fertilizer) plus Pro-TeKt 0-0-3. The 0-0-3 gives the plant the K boost it craves and provides silicon in an opaline form that strengthens cells and helps the plant resist many kinds of cultural stresses. With that combination, you end up with about a 3:1:3 or 3:1:4 ratio that hibiscus will respond very favorably too, but no bloom boosters, please. In fact It's really difficult to make any kind of case for using a bloom booster on any containerized plant, and in a huge % of cases they do exactly the opposite of what they promise - even when applied to plants in the ground.

Al

I was hoping you'd chime in here, tapla. Thanks!

I can honestly say that I never fertilize anything so probably shouldn't recommend fertilizer regimens. My Hibiscus bloom constantly and they do get a LOT of direct sun.

Daisy

Well in NY zone 6 or7 these wont last the winter. In about a month, I want to take them inside again but what is the best way to store them? Should I just bring in the pots as is? They are quite large. I can not store them in sunlight because there isnt any in the basement. I would spray for insects before putting them in my house. Should I prune it down first or wait until the spring? thanks

Allow the plant to dry down while outdoors. Bring it indoors in a cool dark basement. It will enter a consequential dormancy due to the dry state of the soil. You might give it a few dribbles of water during the winter, just to keep the soil from drying completely.

About 3 weeks before your last frost date in spring, unpot the plant and saw off the bottom half of the root mass, bare root the remaining roots, and prune out any problem roots and large roots that are simply unnecessary plumbing. You want to minimize the number of large roots so you can maximize the volume of fine roots - the ones that do all the work. Repot into new soil that drains appropriately. If you can't water your plant w/o the need to worry the soil will remain soggy so long it rots/kills roots or limits root function for extended periods (due to too much water and the lack of oxygen that accompanies that issue) your soil isn't appropriate.

The most significant stumbling block container growers all encounter is not knowing enough about how much sway your soil has over your ability to keep plants healthy. A huge % never move beyond that impediment. Get the soil right, and everything is MUCH easier from that point forward. Why fight your soil for control of your plant's vitality when it's so unnecessary?

Al

Rereading the post I left above will probably be helpful.

Al

Thank you but what about prunning. its large now.

Thank you but what about prunning. its large now.
I was also told to soak in very warm water to make the bugs seep out of the dirt.

If your intent is to force the plant into a consequential dormancy, it doesn't matter if you prune now or in the spring, but DO plan on doing a full repot (as opposed to potting up) in the spring just as you start watering or at the onset of new growth.

Al

Thank you. I will do a warm water soak, spray for insects, prune back a little and then I'll bring it in the basement..