Questions on: Azalea

Ron Smith, Horticulturist, NDSU Extension Service


Q: I purchased a hardy northern azalea two years ago. The first year, it set buds in the fall, but a rabbit ate them during the winter. It again set buds last fall after new growth. It is now happily flowering from the bottom up. Is this normal? I have a lot of buds on the branches from top to bottom. All the buds on the bottom of the plant are blooming. The top buds of the plant are not opening, but are getting new leaves alongside the buds. Do you know why these did not open yet? (e-mail reference)

A: This sounds like an example of snow cover verses no snow cover. The plant is flowering from the base because the snow protected the buds from lethal temperature changes. The flower buds at the top of the plant did not have continuous snow cover and therefore reached a lethal temperature. Flower buds have a lower tolerance for extreme low temperatures than foliar buds, so you have the leafing out that's taking place.


Q: I read your column every week. I must tell you about the azalea I received as a gift a few years ago. After the blossoms fade and fall off, I put it outside for the summer and then the plant starts blooming again. I bring the plant back in the house when fall arrives. Once in the house, the plant continues to bloom. I usually catch rainwater or melt snow to water the plant. The plant continues to grow larger, so it needs repotting on a regular basis. (Pelican Rapids, Minn.)

A: Thanks for being a faithful reader! Thanks also for sharing your success story. You obviously have a knack for getting the azalea to rebloom!


Q: The leaves on my azaleas are turning silver and black on the underside. I think the problem is mites or lacebugs. I have used soap, an insecticide and Bayers. However, I am very late realizing this problem. Everything I have read says to start using these products in the early spring or summer. Is there any hope for the bushes? If I am going to loose these 25 plants, I want to take them out and replant this fall. (e-mail reference)

A: Based on what you have told me, I'd say go ahead and take them out and replant. Next time, begin monitoring the plants as they leaf out in the spring and through the summer to catch anything that might be getting started.


Q: I hope you can help me with an azalea plant problem. Buds will form and they appear healthy, but then they start to turn brown and eventually dry out. The buds are very brittle when I touch them. The leaves around the bud are healthy and the plant continues to grow normally. The plant is very healthy and big. People that see it comment on how beautiful it is. It was full of blooms when I purchased it, but when it bloomed again there were fewer flowers. Now there are no flowers, just dried out buds. (e-mail reference)

A: Dried out flower buds could be a disease known as botrytis or an insect known as thrips. The symptoms are the same. If you are watering overhead, quit and see if that helps. If not, then it is likely thrips. These are very minute insects that get under the flower bud scales and injure the plant tissue with their feeding activity. These are pests that cannot be eliminated, but hopefully can be controlled somewhat. Spray the developing buds with Orthene or Sevin and again 10 days later.


Q: What is wrong with my plants? There are white specks on my azalea plants. Could the specks be bugs? Other leaves are turning brown and so are the leaves on my peace lily. Could it be the new potting soil? Am I watering too much? (Marion, N.D.)

A: It appears that the plants are being overwatered. As long as your potting soil and container are draining freely, the soil shouldn’t be a problem. Allow the soil to dry between waterings and dump any excess from the saucer after 20 to 30 minutes.


Q: I started a three new azaleas from one plant that I had and they are all blooming profusely. What really amazes me is one of the new plants has two colors of flowers. One is the original pink and white and another is more a red-orange, almost solid. I have no other azalea plants in the house. How could this color thing happen? (Wilton, N.D)

A: It could be a somatic (non-sexual) mutation. It often happens in plants, and to keen-eyed nurserymen, this is an opportunity to introduce something new. Enjoy!


Q: I purchased a beautiful azalea plant a few weeks ago. It's done blooming for this time, and I am wondering how to prepare it for the next flowering. How long does it remain dormant? The instruction card that was attached to the plant wasn't much help. Also, I know it's is a little early for planting, but I am wondering what are the best rose varieties to plant in our area this spring. (Wyndmere, N.D.)

A: Azaleas are difficult to rebloom in North Dakota. Our water is generally high in soluble salts, and has an alkaline pH. To make an attempt, I suggest the following procedure:

    1.Keep the plant watered with distilled water.
    2.When spring frosts are history, immerse the pot in a sphagnum peat moss enriched bed on the north side of           the house, keeping it well watered.
    3.On Labor Day weekend, bring the plant back inside, and repot with a high organic potting soil. Keep your           fingers crossed that flower buds have been set and that you will be able to enjoy the flowers once again.

As for roses, I would suggest the shrub-type or prairie roses. The typical hybrid teas and floribundas are too fussy for our climate.


Q: I wrote you last year about an azalea I had that came back into bloom for me. That was around Christmas time and it bloomed up until I set it in the ground in July. I brought it back in before frost and it set buds right away and is blooming very well again. It only has four to six flowers at any one time, but they are much larger this winter due to fertilizing and repotting I guess. I have a new one purchased last Christmas and handled the same way and will let you know if it starts re-blooming. So far, only foliage. (e-mail)

A: Congratulations! It take quite a green thumb and patience to get an azalea to re-bloom in North Dakota. Keep up the good work!


Q: I received a pink azalea plant, and after it died back, I broke off the dead stems and planted it outside on the north side of my garage. Much to my surprise, it continued to grow! Do I need to bring it in during the winter months? I have been told that they are a short-lived houseplant and probably won't flower again. Is this true? (LaMoure, N.D.)

A: Yes, bring your azalea indoors. You might get lucky and have it flower again for you. If not, simply enjoy it as a leafy houseplant.


Q. I have an azalea that I think needs to be repotted, but I am not sure what kind of soil to use. (Mahnomen, Minn.)

A. Yes, azaleas need a soil with a low pH, so get a potting soil specifically designated for this species. If you cannot find any, then incorporate about 50 percent milled sphagnum peat moss with your potting soil when repotting.

Expect (and hope for!) once a year flowering on an indoor azalea.


Q. Can you tell me if the plant in the picture is an azalea? In your column you are always saying that they are hard to grow, but mine is doing beautifully! Can you also give me some information on growing oak trees from acorns? A few years ago I threw some out and now I have a beautiful tree, but I haven't had any luck since. (Wilton, N.D.)

A. Of coursetry to grow something and it won'ttreat it with indifference and it will! Actually you are likely running into one or both of the following problems: the acorns are either immature or an acorn borer has hollowed out the "meat" inside. Basically, you are doing the right thingplanting the seeds in the fall, and looking for something to emerge next spring. Keep a wary eye out for squirrels too!

Yes, that is an azaleathe Indica type. Whatever you are doing keep it up! You've got a beauty!


Q. I have little tiny bugs on my impatiens and now they have spread onto my azalea. What can I use to kill them without killing my plants? I have tried soap water, but that is killing my plants. (Napoleon, N.D.)

A. Try Insecticidal Soap, which is formulated to kill bugs and not plants. It is available anywhere garden supplies are sold.


Q. I have an azalea that flowered and now I am wondering if I should remove the brown parts that are left after the flowers died? I had it outside until it started to get cold, but everyone is telling me to just throw it away! Is there any way to keep it alive, I would hate to have to throw it away. I also would like to know how to overwinter my two miniature pink rose plants that I had in pots this summer? I also need to know how to care for houttuynia? (Valley City, N.D., e-mail)

A. Unfortunately, your friends are right about the azalea. The fact that you have kept it alive this long brings it close to being entered in some record book! Here is a litany of their problems: they don't do well with hard water, alkaline soils or dry heat. They like to be kept moist, but not water-logged. If the soil dries just once, the leaves fall. If you still want to try, I suggest going for an all-peat potting soil, and watering with distilled water. I don't know how big it is, but if you can, place a clear glass (or plastic) fish bowl over the plant once the heat comes on. This will create a "terrarium effect" and keep the humidity high. If this proves to be too unwieldy, place the potted plant in a larger pot that is filled with sphagnum peat moss to keep the humidity high and the roots cool. Place in bright, but indirect light for the winter, in the coolest, above-freezing location in your house.

Don't be discouraged if the plant bites the dust. You honor your mother's memory by at least trying. I suggest photographing it along with some cuttings, and attempting to root them.

I think roses fail as houseplants because people attempt to keep them going on a year-around basis. Give them a winter of rest in a cold location, then begin the "TLC" around mid- to late-March to get them back into bloom again.

Concerning the houttuynia (hoo-TY-ni-a), I would guess that you could do anything you want. It is a hardy perennial for our area, so you could allow it to stay out, and bring it back in for the winter. I am afraid that plants like this will die if not given a winter rest at, or close to, normal winter temperatures. By the way, it is also know as the chameleon plant.


Q: I followed the directions you gave me last spring about keeping my azalea plant alive. Much to my pleasure, the plant is loaded with new blossoms at its site in my
south window. Some branches died off so I did cut them off, making it a little strange looking. But I still pride myself in the fact I kept it alive and going for the most
part, as I don't have a green thumb! I fertilized every two weeks with Rapid grow also. Thanks! (Lamoure, N.D.)

A: I appreciate knowing of your success! I hope it can be inspirational to others as well!


Q: I have had my azalea since the first of March, and now it has started losing its blossoms. What do I do with it now to keep it growing? (Valley City, N.D.)

A: You can do either of the following. One, plant it outside on an east or north exposure for the summer, and make sure it is in plenty of sphagnum peat
moss and that the soil is kept moist. Or two, continue to keep it as a houseplant, but you will need to fertilize it with acidifying fertilizer. Generally,
following the first recommendation gives better results for the plant. In both cases, use liquid fertilizers that are specific for acid-loving plants.


Q: I have two azalea plants, one magnolia, hydrangea and other smaller plants which I know I have to mulch to keep over the winter. When is the best time to mulch these plants and with what type of mulching material? (E-mail reference, Jamestown, N.D.)

A: Mulch should be applied right after the soil freezes, but before the tough winter weather arrives. Now this makes an assumption that both you and I know doesn't always hold true in North Dakota; that the soil freezes first before the snow cover gets here. As to what to use; dried grass clippings, clean oat, wheat, or flax straw, or if you can get it, salt marsh hay. Many people successfully mulch with tree leaves. Or in some cases, branch boughs from evergreens.


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