Ask the Gardener:

The Hibiscus Hiatus Hypothesis

CorrespondentOctober 11, 2013 

Chinese hibiscus (Hibiscus rosa-sinensis) bloom best in a location that is sunny from early morning to the mid-afternoon.

COURTESY OF L.A. JACKSON

Q: I read your article regarding non-flowering morning glories last month, and I am wondering if that applies to my problem with non-flowering hibiscus plants, which I purchased three years ago but never seemed to bloom with those beautiful flowers. Could I be over-fertilizing them or not giving them enough food? I feed them every six weeks. I have also changed their location to a somewhat shadier spot – some have told me they like a northern exposure. Is that the problem? Thanks for any info you can give me.

– Rosemary Burrell, Cary

A: I’m guessing your plants are the popular Chinese hibiscus (Hibiscus rosa-sinensis) beauties. If so, you are taking them away from what they really need – sun. They bloom best in a location that is sunny from early morning to the midafternoon. Any more sun than this, and the flowers tend to be smaller than usual. Any less sun, and, well, what blooms?

Also, check your fertilizer – just like with morning glories. Using a high-nitrogen fertilizer all the time can result in lush foliage at the expense of a full flower show. This doesn’t mean these plants don’t need nitrogen, however. If you go with a fertilizer that has no nitrogen, the leaves will eventually begin to turn yellow. Your best bet is to use a low-nitrogen, time-release fertilizer. Also, for better flower displays, keep them on a regular watering schedule.

When to plant bulbs

Q: I have seen flower bulbs at stores now, and I was wondering if I need to put them right in the ground right after I buy them, or should I wait?

Sharon Taylor, Raleigh

A: You know, it seems there have been a whole lotta Octobers recently that could have been tagged as balmy “Indian summers.” I’m not getting into the spirited global warming debate, but do I know what fall-planted, spring-flowering bulbs like – cool, cool planting grounds. It will be awhile before garden soil is chilled properly for bulbs, since the dense dirt takes much longer to drop in temperature than the air above. So, just as in the past few years, I recommend holding off putting these bulbs in the ground until at least the end of October.

Go ahead and buy bulbs now if you want, but keep them in a cool area until planting time. An unheated basement will usually work. If you have room, the refrigerator is another good place to hold bulbs until they are garden bound. Just remember to store them in mesh bags (for air circulation), and don’t have any ripening fruit (especially apples) in the fridge because they emit ethylene gas, which is detrimental to bulbs.

Wildflower books

Q: I moved here from Michigan in May, and I like to hike. Can you suggest a good book that could help me identify the flowers I have been seeing in the woods? Thanks.

– Lee Thomas, Garner

A: That’s not a hard question to answer. Go to any quality local bookstore and ask for Wild Flowers of North Carolina (Second Edition) by William S. Justice, C. Ritchie Bell and Anne H. Lindsey. This University of North Carolina Press jewel is one of the best books I have found for putting names to the many very nice native blooms that can be found in our woods and fields. And if you want to take it into the wild with you, it also comes in a paperback edition.

L.A. Jackson is the former editor of Carolina Gardener Magazine. Send your garden questions, including the city where you garden, to: askthegardener@newsobserver.com.

News & Observer is pleased to provide this opportunity to share information, experiences and observations about what's in the news. Some of the comments may be reprinted elsewhere in the site or in the newspaper. We encourage lively, open debate on the issues of the day, and ask that you refrain from profanity, hate speech, personal comments and remarks that are off point. Thank you for taking the time to offer your thoughts.

Commenting FAQs | Terms of Service