Hortiscope

Ron Smith, Extension Horticulturist
North Dakota State University

Q: Why won’t my Jade plant grow? What would be the best conditions to keep my jade plant in so that it will grow? It's about 5 inches tall. I got it from a branch of my grandpa’s about three months ago and it sprouted about six new petals since then. Is that normal growth? I had it outside for that three months (I live in northern Indiana). My soil is pretty moist and has been for the last week, but it just won’t get dry. I know that they are "dry soil" plants, so could this have an effect, or am I just plain impatient? (E-mail reference)

A: I vote for impatience. Slow growth is better than fast as far as houseplants go. I assure you, in about 10 years you will be giving away slips and writing to me or another horticulturist asking what you can do with the oversized plant that is driving you out of your room. It is one of these plants that, as it gets bigger little by little, it tends to grow faster. The jade grows best when the soil is kept uniformly moist, but not wet.

Q: I have a large vigorous stand of Staghorn sumac on the back edge of my property. I trim back the front edge of the trees each year so I have both new and well established plants. For some reason my sumac do not turn red in the fall like most sumac do. Could they be missing some nutrients or minerals that could be provided with fertilizer so that we could have the normal fall colored foliage? (E-mail reference, Aberdeen, S.D.)

A: Good question. I would tend to think that you are likely being too good to them -- water, fertilizer, etc. Try neglecting them a little and see if that results in better fall color. If not, then it is likely a genetic deficiency and nothing can be done about it.

Q: I am interested in putting in some ornamental grasses as a background for my garden. I'd like them to grow to 4-5 feet tall, and would like one for the shade, if possible, and one for sunny spots. Can you suggest good varieties, suitable for our winters and short growing seasons? (E-mail reference, Fargo, N.D.)

A: There are several ornamental grasses you can use. There are none that do well in shade. The will grow, but will flop over easily and not look as attractive. Here is the list: big bluestem - about 6 feet; Indiangrass - about 6 feet; 'Karl Foerster' feather reed grass -- 4 to 5 feet; Feezy's ribbon grass -- 3 to 5 feet; prairie cord grass (Spartina pectinata) -- 5 to 7 feet (quite aggressive in moist areas); Canada wild rye -- 5 feet.

Q: Do the wild rose seeds I picked from the road ditch have any chance of growing? I dried them near a fan at room temp for a few days. Do they have to have a cold soak? Will I need more than the 2 teaspooons of seed to compensate for possible low germination or viability? Is it better to direct seed or can I start them indoors? Any guess on what the small white grubs in many rose hips are? The hips that have grubs have small holes as if an insect laid eggs, and I might have seen an egg in some of the hips, but I threw away any thing that looked like a grub egg or in any way damaged seed. (E-mail reference, Fargo, N.D.)

A: Rose hips should be collected as soon as they are ripe but before the flesh starts to soften. Stratify the extracted seeds immediately at temperatures ranging between 35 and 40 degrees for up to six months. If this is not acceptable, then simply sow the seeds in a prepared bed in a row or scattered over the prepared area. The seedlings will emerge next spring. Concerning the insect, it is a rose hip borer. Simply throw those hips away where penetration has been made.

Q: I was wondering, what is the best time to move some rhubarb plants, strawberry plants and mums? (E-mail reference, Morris, M.N.)

A: The best time is: rhubarb, early spring; strawberry plants, spring; mums, in the fall.

Q: Our apple tree was loaded down with apples and the branches overloaded and bending to the ground. We appreciate the apples but need advice on pruning. Can we trim off those full branches and when should we prune? (Jamestown, N.D.)

A: You need to give the loaded branches as much support as possible to avoid breakage. The overloading can be avoided in future years by hand thinning in late May when the fruit is small.

Pruning on fruit trees is done in the early spring while the plants are still dormant or leafless.

Q: Why doesn’t my reblooming iris bloom? They are only one year old but are nice and big. I was told that they need more fertilizer. (Tyndall, S.D.)

A: Not likely, as I have iris that I have never fertilized and they bloom profusely! More likely it could be insufficient direct sunlight or they are planted too deeply. I’d suggest waiting one more year to see if they bloom for you in 2001. If not, then move them to a sunnier location.

Q: I recently harvested about a dozen gourds of all sizes and shapes. Now I would like to know how to preserve them to keep them from shriveling and rotting. I plan to use them in a "horn of plenty" for decoration. (Eureka, S.D.)

A: Drill a small hole in the blossom end of the gourd and hang them to dry. When the seeds rattle inside when the gourd is shaken, it is dry enough to either wax or shellac.

Q: A client is wondering if apples should be picked before the first frost or do they need a frost? Also, how cold and how long? (E-mail reference, Linton, N.D.)

A: The first frost of the year is almost never detrimental to apples because of the foliage protection. They can normally tolerate temps down to 27 degrees for the night with the foliage. It is later in the fall when most of the foliage is gone and the tree is still carrying apples that such a freeze could damage the apples, but then only for storage purposes, as they can then be immediately used for making apple sauce or juice.

Q: I was just wondering, when it starts to get cold at night (around 25 - 30 degrees) what is the best way to cover a few things in my garden? Are tarps and plastic good to use or do you know of something else that works good? I have green peppers, watermelon, and cantaloupe. And also, is it even worth to cover them when the growing season is almost over? (E-mail reference, Battle View, N.D.)

A: Aha! You asked me both a technical question and a personal opinion. Here are the answers:

Tarps, newspapers, plastic or anything that can keep a layer of air between the plants and the outside air will provide temporary protection from brief freezes, down to 27-28 degrees. Personal opinion: it isn't worth it. I don’t cover my garden or plots.

Q: I have a question about my Croton houseplant. May I cut it off since it lost all the bottom leaves? Can I replant the top bushy plant where the leaves are good? I do have a new seedling that is doing great at the bottom. Does this Croton plant ever need fertilizer? (Gackle, N.D.)

A: Crotons can be cut back when they become too large or ungainly looking. The stem that has been cut back will eventually make new growth. When you cut the Croton (more properly known as Codiaeums) it will bleed a milky latex typical of members of the Euphorbiaceae family. Spray the cut ends with water or dust them with powdered charcoal to stop the flow of latex. With the cutting, reduce it to about 6 inches long for faster rooting and easier handling. Plant the cutting in a 3-inch pot of moist, equal parts mix of peat moss and coarse sand or perlite and enclose everything in a clear plastic bag and place the plant where it can get plenty of bright, but indirect light every day. When new growth is evident, that means the cutting has rooted and the bag can be removed. Next spring it will likely need repotting as the roots will have filled the 3-inch pot space completely.

Q: My parents have a young silver maple tree planted in their front lawn, currently about 8 feet high. While they are aware that a silver maple is not a "bush" type of tree, they are wondering if by cutting the top off the tree would then "bush out" instead of continuing to grow upward? (E-mail reference, Virginia)

A: I don't like the idea of "topping" a tree, especially one with opposite leaf bud arrangements like maples have, as it is difficult to get directional growth in such a case, as compared to a tree like an oak, for example, that has an alternate leaf bud arrangement. A bushy type tree that would be a better selection is either an Amur maple or Tatarian maple. These generally come with a multi-stem arrangement that allows them to be more spreading in character than simply upright. Silver maples are naturally a single stemmed tree that typically develop into a loose, oval form at maturity. Silver maples typically have a weak branching system, so we try to encourage proper pruning to help compensate for that shortcoming. A topping pruning procedure would only exacerbate the problem further. Allow the tree to grow naturally with a minimum of corrective pruning, or replace it with one that will have the form that you desire.

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Do you have a gardening or houseplant question? Write to Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or e-mail to Ron Smith at ronsmith@ndsuext.nodak.edu.

Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Gary Moran, (701) 231-7865