I use a weed killer to kill the weeds that grow in my beds and in cracks in concrete. While it kills the weeds I spray, they always eventually come back. Is there anything more effective or potent I can use that will keep the weeds from coming back? — Tyler
The postemergence weed killers we use to control actively growing weeds generally do a good job of killing them. But if you are dealing with perennial weeds with persistent below ground parts (like bulbs or rhizomes), you need to use a systemic herbicide.
Systemic herbicides are sprayed onto the foliage of the weeds. They are absorbed by the leaves, get into the weed’s circulatory system and move throughout the plant — killing both above ground and below ground parts.
If you use a contact herbicide that just burns down the foliage and leaves the perennial below ground parts alive, the weeds simply grow back. This may be a factor in what you are experiencing. If you are dealing with perennial weeds, be sure to use a systemic herbicide.
The other issue in weeds returning after the use of a weed killer involves weed seeds. While a contact or systemic herbicide will control growing weeds, they have no effect on weed seeds in the soil. After the growing weeds are dead, at some point weed seeds begin to germinate, and you once again have a weed issue that needs to be dealt with.
There is something you can do about this, however. Preemergence herbicides (or weed preventers) are applied to areas where the growing weeds have been controlled with a postemergence herbicide. When applied to the soil, they kill any weed seeds that try to germinate. They are active for several months before they are reapplied. They only work on germinating seeds and will not keep perennial weeds from sprouting from rhizomes or bulbs after the top is killed back. Be sure to use a systemic postemergence weed killer when dealing with perennial weeds.
So, when dealing with weeds, a two-pronged approach is often helpful. First, kill off the existing weeds with a postemergence herbicide. If applying in beds be very careful not to get these on desirable plants or use an appropriate selective herbicide. As those weeds begin to die, apply a preemergence herbicide like Amaze, Preen or many other brands.
About 10 years ago, I put in a Japanese maple, which has been a joy, so I bought another one three years ago. It is now starting to die back and it looks bad. I will probably have to cut it down. Are there varieties that are better for our area? I need to replace this dying tree but am a bit confused as to how to find a good one. — John
Bloodgood is one of the few cultivars that has been fairly widely planted and has a history of growing well in south Louisiana. Cultivars recommended by the University of Florida Extension Service include Bloodgood, Sango-kaku (coral bark Japanese maple), Butterflies, Kagiri Nishiki, Moonfire and Seiryu. Hopefully, local nurseries will carry some of these.
It’s possible that the problem with your second Japanese maple tree is more about the location where the tree was planted than what variety it is. I say this because most varieties seem to do reasonably well here with good care and a good location in the landscape.
Japanese maples tend to be more reliable planted in a location that has excellent drainage and shade in the afternoon or dappled shade through the day. They must be watered carefully during summer. They may need irrigation during dry periods, but they are prone to root rot if watered excessively.
GARDEN TIPS
Gardeners often place their tropical plants in containers outside for the summer and bring them indoors during winter. Move any plants you intend to winter indoors to very shady areas outside, such as under carports or trees, for the next three or four weeks. This will allow them to adjust to lower light intensities before you bring them inside where light is more limited. Make sure you place plants in front of bright windows when you bring them indoors.
Plant a crop of radish seeds in the garden now for harvesting around Thanksgiving. Once the seeds come up, make sure you thin the plants to a spacing of 2 inches apart. Otherwise the roots will not develop properly.
Purchase and plant strawberry plants this month into well-prepared beds in your vegetable gardens (or even in flowerbeds) in full sun with good drainage. Recommended cultivars are Festival, Camarosa, Camino Real and Chandler.
Purchase tulip and hyacinth bulbs in the next few weeks to give them enough time in your refrigerator for the eight weeks of chilling they need before being planted out in late December or early January. Other types of spring flowering bulbs do not need to be refrigerated and can be planted anytime now through early December.
Make sure you mulch new beds of cool-season bedding plants as soon as they are planted to control weeds. It’s also helpful to water them in with a soluble fertilizer to get them off to a good start. Repeat the soluble fertilizer application every 10 days until the plants begin to grow well.
GARDEN QUOTE
“I found myself aching to order up sacks of bulbs, to lift my trowel, to slice into the earth, and tuck away what amounts to hope, faith and promise.” Barbara Mahany, journalist and blogger
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