Hibiscus

I grow several hibiscus bushes that I over-winter in my greenhouse. Many of them are hand-me-downs from my mother and others who fall in love with the plants at Bachman's, but later in the fall, decide that they don't want to keep them going. I suspect that hibiscus abandonment is the norm. This is a shame because with a little know-how, hibiscus can be very rewarding.

There are 3 lessons that you need to learn to be successful with hibiscus: two pertain to watering and one to fertilization.

In the summer when the temperatures are between 60 ? 95 degrees, hibiscuses need constant water. Since most of us have them in a container, this means watering every morning and during 90+ degree weather, giving them some water at night. You can't really over-water hibiscus during the summer months (unless your pot doesn't drain or something - never given it a try.) When in doubt, apply water.

Fertilize once a week with a liquid fertilizer that has low phosphorus (the middle number) but high nitrogen (first number) and potash (third number.) This is the trick: those fertilizers that everyone buys in Minnesota for tomatoes and annuals usually have outrageous amounts of phosphorus and hibiscus does not like that (forget standard Miracle Grow.) You will have a tough time finding the proper mix like 17-5-24, so you will have to create your own.

Here is what I do: use half-strength grass fertilizer (often 32-5-5) on a weekly basis and mix some muriate of potash into the soil once a season. This will ensure dark green leaf color and vibrant abundant flowers.

The last thing to know is how to care for the plant in the winter. Bring the plant inside before any threat of frost and when temperatures are falling below 50 degrees (the plant will have stopped growing at that temperature.) It still needs light and regular water. Remember that the humidity in Minnesota homes in the winter is really low so water will be needed a couple of times a week even though growth is slow. I have had quite a few blooms in the house all winter by following a regular watering schedule.