I have been very successful growing impatiens and several other annuals for clients. This year, I am having a hard time growing marigolds and ageratums (different beds, same property). I prepare the soil the same way and fertilize the same. The flowers look distorted and kind of puny. I'm also having a hard time controlling the weeds in the grass. What is going on? — via the Internet
It sounds like you are considering all your options to determine the problem. A few more questions to ask are: What may be present that you are not aware of, such as a chemical spill, gas leak or a concrete cleanout area? You may be able to answer these questions simply by noticing contaminants or smelling odd odors when working with the soil. Check with the owner regarding any treatments applied to the area or construction practices that may have damaged the area. Did you obtain these flowers from the same supplier as those you installed in other beds? What chemicals may have been applied nearby, to the turf or landscape plants?
How are you controlling the turf weeds? If you applied herbicides to control turf weeds, it is possible drift from the herbicide is affecting the flowers. Most broadleaf post-emergent herbicides can injure non-target plants, and being able to identify the damage is the challenge. Often plantsmen describe herbicide damage as yielding curled leaves or twisted stems. However, plant growth regulator herbicides, such as 2,4-D, dicamba and mecoprop, have varying affects depending on the rate and species. Recent research at North Dakota State University was performed to identify how 2,4-D, dicamba and 3-way herbicide drift affected eight different annual flower species. Some injury did include curled leaves on some flower species, especially on ageratum and alyssum, but some species had no foliar injury at all. Injury varied from simply reducing flowering to tip dieback; elongated flower stems, which caused flower clusters to be more loose or open; flower bud death; tissue swelling at the base of petioles; callus formation and root initiation along the stem. Some species even performed better when treated than when not. The growth suppression may only be noticeable when grown next to untreated plants. In general, only some of these symptoms were visible on some species. Look back over your records of herbicide applications to see if this offers a clue to the symptoms you are observing. If the plants are not attractive and detract from the appearance of the property, it may be worth removing those flowers and either dressing up the area with mulch or looking for other plants to replace them.
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