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October
6, 2005
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Garden Club
Frequently Asked Questions Question: I ordered a package of dahlias from your nursery about 4 years ago. Each year I dig them up in the fall and replant in the spring. They are beautiful flowers but I am never sure that I am actually keeping them correctly during the winter. I cover them with peat moss and keep in a dark place in my basement. Should I be doing something else with these plants that would enhance the flowers in the spring?Also, I have a Wisteria plant over my trellis and would like to cut it back to keep it under control. When should I prune this plant and how much should I cut off, if any?Answer: Your procedure is keeping the dahlias alive over the winter and that's all you can expect. Dahlias normally bloom in mid-summer. You can increase the number of blooms and the earliness of the blossom time by starting the dahlias indoors in pots. Good culture will bring lots more blossoms to your dahlias. Dahlias are gross feeders and they resent dryness. Mix lots of Chesapeake Blue crab compost and Bulb-Tone into the soil at planting. Use water retaining polymers also when planting. Feed monthly with Bulb-Tone or Flower-Tone and use SeaMate liquid fertilizer every time you water.You may cut back your Wisteria as far as you feel necessary, if you do so right after blooming. Question: Hi Alan, I listen to your show every Saturday, quick question, I have a lot of palm/tropical plants. They do good all summer long, but during the winter in my dark/cold basement they start to look a little bit beaten up. Can I give them a shot of something to really have them doing super good before they migrate to the basement? Answer: Spray the foliage with Messenger now and again in 3 weeks. Do not feed until early March. Then feed with SeaMate every time you water. The problem is that the cold and darkness are causing the plants to go into semi-dormancy. There is not much you can do in the winter to compensate for that. (Is it possible to increase the light and heat?)Spraying the foliage with Messenger every 3 weeks once the plants start to look good until mid-November should make the plants stronger next year and better able to deal with the cold and darkness. Question: I have several hydrangeas that produced beautiful flowers this spring, but whose leaves now have brown/rust spots of various sizes. What is the name of this ailment and how should I treat the plants? Also, given the date and the appearance of the plants, is it too early to cut the plants back?Answer: I presume your hydrangeas are either pink or blue flowering, but not the new Endless Summer. If so, you have Hydrangea macrophylla and serrata varieties. If you cut back these varieties now, you will have little bloom next year. The only time you can cut these back, without reducing the bloom, is just as the bloom fades in August. In general, you should not cut these hydrangeas back unless they are too tall. Re-blooming hydrangeas, such as Endless Summer, can be cut back at anytime from late winter through July, just before the new leaves emerge.Your hydrangeas have a leaf fungus; it is too late to treat this season. To help prevent re-infestation, rake up all of the leaves as they fall and dispose of them. Next spring, starting when the new leaves emerge, spray with Messenger, a harpin protein, on 3 week intervals thru August. This is an organic and may be sufficient. At the first sign of leaf spotting if any, spray with Infuse - a chemical fungicide - also on three week intervals. Discontinue Messenger when using Infuse.Question: I always get confused about fall gardening. As a general rule, should you cut down most shrubs/perennials in the fall? Also, when is the best time to fertilize shrubs and trees in the fall? I must admit, it seems counter-intuitive to fertilize in the fall since most shrubs/trees are doing dormant for the season. Also, any specific advice on clematis, should I cut this down? Answer: Here are some general rules for you to follow: 1. When perennials turn brown cut back just the brown parts. Many perennials stay green at the base until well into winter and then turn brown after a solid freeze. If they are offensive, these basal brown rosettes can be cut back in early spring. If you are only going to do only one fall perennial cut back, do it in late November. 2. Most shrubs should be cut back right after flowering - except mid to late summer and fall blooming shrubs. Pruning is a stimulative process. These late-blooming shrubs can be harmed in the winter if they are stimulated to late fall growth. Instead, delay pruning these summer and fall blooming shrubs, like butterfly bushes, vitex and crape myrtles, until early spring. 3. We recommend fertilization of trees, shrubs and perennials in late fall with organic fertilizers. Applied in late November, these organic fertilizers will not activate until early spring when the soil warms. (Organic fertilizers are broken down by micro-organisms that are not active when the soil temperature is below 50 degrees). However, they will work down into the soil with the melting winter snow and the frost action in the soil. 4. Clematis have different pruning requirements depending upon the variety. However, I have found any easy rule to follow is to cut all clematis to the ground in spring only when they have turned into a tangled, unsightly mass - usually every 3 to 5 years. On some varieties you will lose the massive early bloom the year it was cut down. However, often that loss will be partially compensated by an unusually prolific late summer/fall bloom. All clematis benefit from a light shearing right after the initial heavy bloom. Question: On your recommendation I planted winter blooming Jasmine ( Jasminum nudiflorum) as a ground cover on my hillside. It has filled in beautifully and we love the effect. We tried so many things on this scorched hillside and I can't believe we finally found something that worked.My question is the Jasmine is sending up an occasional stem arching about a foot over the ground cover mass. Should I cut them back and if so when? Answer: The arching stems definitely need to be cut back but they have already set buds for next February's blooms. If you cut them back now you will lose that little bit of extra bloom. On the other hand without the over arching stem the Jasmine ground cover will look neater over the winter. So the choice in timing is yours, but the stems do need to be cut back to keep the Jasmine as a ground hugging cover. Question: A few weeks ago I read about your feature plant Colchicum the Giant and I bought some. A friend has some double flowering colchicum that look like little roses on the ground. Do you have any of those, they really are pretty?Answer: Undoubtedly your friend has a colchicum called 'Water Lily.' I agree it is the most beautiful of all of the colchicums but it is quite a bit more expensive (3/$13.85). I encourage you to try a few. 'Water Lily' is just as easy to grow as the Giant. |
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