Don Kinzler, Published September 28 2012
Hortiscope: Water less in fallQ: I’m hoping you can help me. I received a huge cymbidium orchid plant that was on the downside of its blooming. There were seven or eight bulbs squeezed into a
7-inch pot. I had difficulty watering it because everything was above the top edge of the pot. I would water in every available spot but ended up having water spilled all over.
I went to the florist where it had been purchased, but no one there was able to give me any answers about watering. Also, it was in a pot with no holes on the bottom, so I couldn’t water it from the bottom. The only suggestion was to use ice cubes, but they would not have stayed in that small of a pot.
I purchased a 9-inch pot that has drainage and used an orchid potting medium. I carefully removed the orchid root ball and placed it in the new medium and then packed more new medium snuggly around the sides. Later, I decided it was looking poorly because I was giving it too much water, so I quit watering it for about two weeks. The plant was located in a corner of my living room where it received bright but not direct sunlight. I was checking for dampness one day and found that the air conditioner was blowing cold air on it.
I decided that was probably more of a problem than overwatering, so I moved it closer to the dining area. The plant is on the same wall, so it receives the same amount of light, but no more cold air. I have not given it any fertilizer.
I have checked for insects but haven’t found any. My problem is that the leaves turn yellow, then brown and drop off. The bulbs also have shriveled and dried. There are 10 new shoots coming up from the shriveled bulbs, so I guess it’s not dead. Does it go through some sort of recycling period? I’ve read almost everything I could find about cymbidiums, but I’m stymied as to what to do next. (email
A: I’ve never grown cymbidiums and don’t have any associates who have worked with this species. All I can tell you is what I read in my reference library. The magic formula for success is rest, cooler temperatures at night, as much light as possible in the fall and sufficient humidity at all times.
Water is needed in copious amounts from March through the end of September. Past that time, water less and do not fertilize. The use of cool, circulating air is apparently important to this species of orchid, so an oscillating fan would be suggested. I hope this information is useful. If not, then all I can hope for is that some reader with successful experiences growing cymbidiums will provide more detail that may be useful to you.
Q: We have dandelions and other weeds in our lawn. I hear that fall is the best time to control the weeds. Is it too dry to do any good this fall? What is the best way to fight dandelions? (Gackle, N.D.)
A: Weeds that have been subjected to dry, hot weather through most of the summer are pretty tough customers right now and might be resistant to standard herbicide treatments. Also, any herbicide treatment right now would put a lawn under even more stress. If you want to treat your lawn for weeds, do a week’s worth of watering to soften up the weeds somewhat and get the grass restimulated to grow a little.
There are many products on the market to do the job. One product is Trimec. It is very effective against broadleaf weeds such as dandelions.
Q: Where would we buy some northern acclaim honeylocusts? Are there any local retailers? I think next spring we would like to get some to put near the house. Also, we had our soil tested in areas where we are having trouble getting grass to grow. The conductivity was rather high (soluble salts at 6.10 millimhos per centimeter) and the soil had a pH of 8.7. Larry Swenson from NDSU recommended we purchase Fulz alkali grass seed. However, I also am curious if there are any bushes or trees that could tolerate these conditions? Is there a way to improve the soil in these areas? (email reference)
A: Local garden centers should carry honeylocusts next spring. They are beautiful trees worth having on your property. The soluble salts are extremely high, so the cost of correcting that high a salt content and elevated pH would be too prohibitive to consider. In Texas, where we ran into similar situations, we’d build berms with high-quality soil and plant the trees with the rootball not in the salty soil. It also is important that the area is watered with high-quality (low-salt) water. There is no plant material of any nature that will grow in soil with elevated salts and a pH that are that extreme.
Q: We have three autumn blaze maples in our yard. Two of them are really beautiful and were planted 15 years ago. The other tree was planted about five years ago. The younger tree died during the last two years. We suspect we didn’t water it enough. The bark on the west and south side of the dead tree is cracked and peeling off. One of the older trees looks healthy but also has pretty extensive bark peeling on the west side from the ground to the lower branches.
Both of these trees are exposed to west and south sun and wind. We have been very dry and hot here for the past two summers and our winters have been mild. Our other older tree is on the east side of the house and shaded from the west sunlight and does not appear to have the bark peeling issue. We are concerned that our older tree is in danger and wondering what we can do. What watering requirements would you recommend we provide these trees during the various seasons? (Wichita, Kan.)
A: These, or any trees for that matter, need supplemental water inputs when the region is under high temperatures and drought conditions. If the decision is made to do some watering, some kind of consistency must be established. Give the trees a good soaking under the drip line twice a month. If an unexpected rain event of any consequence should occur, that should not disrupt anything as far as your irrigation schedule goes. Avoid any unneeded pruning, especially the lower branches, and hold off on excessive fertilization because both actions will contribute to the problems you describe. Also, as strange as it may seem,
I’d encourage wrapping the trunks of the trees during the winter months until a good, corky bark has developed to protect the trees from temperature shifts and dehydrating winds. Lastly, contact the Kansas State University Extension agent in your county. Go to http://www.ksre.ksu.edu/map.aspx and click on your county to seek local advice.
Q: I have a clematis plants that has been with me for 20-plus years. I had a honeysuckle vine sitting next to it. Overnight, the leaves on the honeysuckle turned white from a powderlike substance. I tore out the honeysuckle vine but noticed this morning that some of the leaves on my clematis also have white spots. I do not want to lose the clematis. What do I need to do? It is starting its second bloom because the weather has cooled down. (email reference)
A: This very likely is powdery mildew. If you see it on just a couple of leaves, remove them and spray the plant with a fungicide to prevent it from spreading.
There are several products on the market to use for this purpose. Repeat the application at least one more time (10 to 14 days after initial application).
The hot and humid weather conditions at this time of year are conducive to powdery mildew development.
Q: Your site is very informative. I live in northeastern Wyoming and am planting some Colorado blue spruce trees that weigh approximately 750 pounds each. I am lining my eastern-facing property line. What is the ideal spacing between trees?
What is a good depth for the hole? I never have planted trees this large. With smaller trees, I would dig the hole deep enough so that the rootball was slightly above grade. I have seen others dig about a 2-foot-deep hole and mound up to the rootball. I was told this helps get water to the root system until it becomes established in our arid Wyoming climate. Thank you for your advice. (email reference)
A: There are all kinds of recommendations for proper tree planting. Some are valid, while others are not. I have an unbiased, nonopinionated method of planting trees that you can read at http://www.treesaregood.com/treecare/tree_planting.aspx. With trees the size you are talking about, you only want to move them once. As for the spacing, that is up to you. The spread of this species often fools the uninitiated because they can get as broad as 25 feet or more. It depends on the condition of the site.
There is another website you can reference at http://www.ag.ndsu.edu/trees/handbook/th-3-177.pdf. When I worked on landscape crews during my younger days, the Colorado blue spruce was a homeowner favorite to plant. I grew to hate this tree species because of the hypodermic-type needles they possess. When we were done planting, we looked like losers in a wrestling match with porcupines. I hope you have good help in this undertaking and that the weather conditions will allow you to wear leather gloves and a denim jacket.
Q: First of all, I want to thank you for the advice you gave me on what to do about apple maggots. We did what you suggested and, so far, I have not cut into an apple with apple maggot damage. Considering our drought, the apples taste great. However, I have a few more questions for you. My husband and I planted some perennials next to the foundation on the north side of our house. Will we need to cover these plants with something to protect them during the winter? My last question is about woodbines. I think the actual name of it is Virginia creeper. We have it on a chain-link fence surrounding our dog kennel. We now have found it growing in our tree grove. Is it OK to have this plant in the trees? We do not want it to damage any of our trees. We have found it clinging to some small trees. Should I be pulling it out rather than letting it grow in the grove? Any help you can give me will be greatly appreciated. (email reference)
A: Glad things worked out well for your apple tree. The perennials you planted will not need any extra protection this fall to get them through the winter months. They should survive even if we have minimal snow cover. The woodbine will out-compete the small trees in growth and steal the sunshine needed for good growth. In addition, the vine, once established on the trees, will stay there and become woodier through time and eventually girdling the tree. It is best to keep it confined to the fence and out of the trees.
Q: We have a tree the previous owners called a Canadian red chokeberry. It does match the descriptions I’ve read, although I’ve never seen fruit on the tree in the 13 years we’ve had it. This summer, we’ve noticed a lot of thick, gooey, clear discharge on the trunk. Do you know what might cause this and what we can do to help the tree? (email reference)
A: This is an indication of borer activity, which is usually the spelling of doom for the tree. Borers attack trees that are under stress, which many trees in North Dakota are. Based on your description, I’d say the tree needs to be removed. However, if you could send me a photo or two of the tree showing the exudate, I can give you a more definite answer.
Q: I had my landscaper plant 15 arborvitaes along a wooden fence in my yard this past June. The landscaper made a well around each one and said to water them by filling the hole with water every other day, especially if it is hot. I have been doing that and all seem to look good. The yard gets full sun all day. I am just concerned about the back of the trees facing the fence. However, they are not showing any brown leaves yet. How should I proceed now that it is September? What should I do this fall and winter? How about fertilizer and trimming? (Flushing, N.Y.)
A: It sounds like your landscaper did everything correctly and offered you good advice, which you have followed and are witnessing success in your planting. As the weather cools and rainfall frequency increases through the fall and early winter, you can back off significantly on your watering regime. While you don’t want them to go into winter bone dry, they shouldn’t continue to be watered the same way. Their need for water decreases with reduced temperatures, shorter days and the increased delivery of water by Mother Nature. You want damp soil around the plants going into winter, so don’t let the soil become soggy or bone dry. As for the side against the fence, you probably will want to keep that trimmed as the plants continue to expand in size. Contact with the fence won’t cause any problems initially, but if your objective is to keep the plants full and lush all around the plants, you will want to maintain some space between the fence and foliage to allow for air circulation and healthier-looking foliage.
Depending on your exposure, you might want to erect a screen around the plantings to keep the direct rays of the winter sunlight off the foliage this first year. However, don’t wrap the plants with burlap. Erect a screen on the south and southwestern sides. If there is no direct exposure from winter sun, then this move is not needed. You also should contact your competent landscaper to see what he would recommend. Coarsely woven burlap typically is used for this purpose. If that is unavailable, frost blanket material would serve the same purpose.
To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or email email@example.com.
For answers to general horticultural questions, go to http://www.ag.ndsu.edu/horticulture.