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Don Kinzler, Published December 07 2012

Hortiscope: Cut your roses back in fall for best results

Q: I have several questions about different plants. I would like to know if I can trim a schefflera plant. I have a nice plant that was given to me for my son’s funeral. The plant sits in my enclosed sunroom by an east window. It is very big, so I’m wondering if I can cut some of it off. I am now covering my rose bushes. The bushes only produced a few flowers this year but were gorgeous last year. The bushes grew very tall, so I wonder if I didn’t trim enough last year before I covered them for the winter.

I have a lovely African violet that I would like to keep. I have transplanted it several times. It never makes new plants, so all I do is place the old one in new soil, but that is not working anymore. I remember my mother-in-law would cut off a leaf and stick it in planting soil and a new plant would grow. She must have done more than that because my luck has produced a dead leaf stuck in the dirt. (email)

A: Schefflera plants can be pruned to keep them sized for the environment and the container they are in. Make the cuts with a clean, sharp hand pruner or knife. I’ve always suggested cutting roses back in the fall to get them down to size so they can be covered for winter protection.

After the roses are uncovered in the spring is a good time to trim them back to the starting size you want, and it’s based on the kind of roses one has. Roses bloom on new growth and generally are pruned during the summer to keep them in size and to extend their flowering ability. I’m hoping that yours didn’t grow up from below the graft union. This sometimes happens when the snow cover is light and the scion (budwood) is killed off by low temperatures.

African violets are one of the easiest houseplants to propagate asexually. The secret is to have a pasteurized or sterile media, high humidity, healthy leaves and patience. Once you’ve selected a healthy, young leaf to propagate, make a slanting cut on the petiole to provide more surface area for new plantlets to develop. This should happen in six to eight weeks. The mother leaf eventually dies as the new leaflets continue to develop. Carefully cutting them away from the declining leaf will help the new plants get established.

Q: I have an angel wing begonia plant that I started from a cutting more than three years ago. I’ve started several other plants from this plant and put them together in a large pot. They never have flowered. It is located in a very happy place, which is on my kitchen island under a skylight.

The plant grows like crazy. I water it every other day. I’ve heard that the flowers are very pretty but never have seen them. Should I let it dry out between watering? I tried an experiment by breaking off a leaf, rooting it in a glass of water and putting it in a small pot. It has sustained its own little life without sprouting any other leaves or canes. Have you ever heard of this? Will it be an eternal leaf? (email)

A: It will be an eternal leaf. If you take the leaf or another one and lay it across the media and then make small slices across some veins, new plantlets will grow and the original leaf deteriorate. I am surprised that this has not happened at the base of the leaf you have stuck in the water. You are overwatering. You must have good drainage or you would have rotted everything a long time ago. Allow the soil media to dry before watering. This should slightly stress the plant enough to bring it into flower.

Gardening or houseplant questions can be directed to: Hortiscope, Box 6050, NDSU Dept. 7670, Fargo, ND 58108-6050 or ronald.smith@ndsu.edu

Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations

Q: Can I take the ivy that I have had outside in my summer pots and transplant them into the ground in November here in Massachusetts? I believe the ivy is some form of English ivy. Will it survive the winter and grow back in spring? (email reference)

A: Can’t say for certain. If the plant is true English ivy and planted in a protected location where it will not be exposed to winter wind/sunburn, it just might. It also depends on how or if the plant was hardened off to the upcoming winter. If you want to hedge your bets, take a couple of cuttings to root indoors in case the winter turns out to be too severe for the plant.

Q: I have a 35-year-old indoor hibiscus. The plant is thriving again after having had a traumatic year. In the summer of 2011, I moved it outside for the first time and was extremely pleased with its profusion of blooms. Then it got quite cold, so I sprayed on a coating to protect it and bought some cloth to protect it from freezing. I also brought it inside. That’s when it crashed and looked like it died. After a lot of loving care (including pruning), it bounced back around March. By June, it was blooming. However, all of a sudden the leaves drooped. Based on some of your answers to people, it sounds like I might have overwatered it. I’m sure that I compounded the situation by giving it more water. When it didn’t perk up again, I decided maybe I should dry it out. Yesterday, I fertilized it and watered it again. Today, I decided to take out some of the soil to see if I saw any insects or could detect any mold. I didn’t find any problems. I guess my best approach is to not water it until it completely dries out. If that’s the approach, approximately how long should I wait to water it again? Do you have any other suggestions? I’m sentimentally attached to this plant because it has been in the family for 35 years. (San Jose, Calif.)

A: Isn’t it amazing how attached we can get to plants? There isn’t much you can do except to allow the soil to dry for at least two weeks to see what happens. Before building up your hopes, I would suggest that you use your thumbnail to scrape off the outer layer of bark on several of the main stems or trunk to see if the cambium is alive. If it is, there is a chance if might recover. If not, then all the tender, loving care you give it will not bring it back. If the cambial tissue is green, then go ahead and give the plant a good shot of water after two weeks of drying the soil. Give it enough water so it comes out of the bottom of the container. I’m assuming you used fresh potting soil to repot after examining the roots. That is something you should do if you find green cambium under the bark and before giving it any water.

Q: What grass do you recommend planting in a very shady yard? Is it too late to put some seed on the lawn? Thank you. (Fargo)

A: Shade-tolerant grass will be the fine-leaf fescues. Any mixture labeled shady lawn mix will have the majority of its components made up of creeping red fescue cultivars. From a calendar standpoint, it is too late put seed on the lawn. However, if the ground isn’t frozen and you can get the seed scratched into the surface somewhat, then go for it. The seed will remain dormant but will sprout and grow quickly next spring.

Q: I have a chenille plant that is growing great. I have it in a room that gets lots of light but not direct sun on the plant (at least most of the time). The plant is now showing yellowing at the tips of the leaf points. Is this a lack of fertilizer, sun shining on it some of the time or a pest of some sort? (email)

A: It sounds like salt burn. This could be caused by keeping the plant in a pot that is not draining well enough, so the fertilizer or water salts are building up to a point where tip burn is now taking place. I’d suggest repotting the plant in a free-flowing pot using fresh potting soil. Fertilize lightly every two weeks during active periods of growth. It could be that the plant is getting too much sun, so try moving it back a little from the source. Also, it could be low humidity or just senescence of the older leaves.

Q: The cottonwood tree in my backyard has a branch that is forming (for lack of a better term) in two spots. What is causing this condition? Also, what would cause six or so rust-colored spots on the base of a cottonwood tree? (email)

A: I think you mean that the branch is forming a “Y” crotch, which could be dangerous as the tree lays down more wood in that area with the developing branches. I suggest selecting one or the other and make that the leader. Generally, the lesser of the two is selected to be removed. The rust-colored spots could be the result of slime flux, which is an exuding of the sap that has fermented in the interior of the tree. Have the tree checked by a forester or arborist to make sure the core hasn’t rotted. These are my best guesses based on your description.


Gardening or houseplant questions can be directed to: Hortiscope, Box 6050, NDSU Dept. 7670, Fargo, ND 58108-6050 or ronald.smith@ndsu.edu

Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations