Plants, inside and out, are part of nature. They will host insects, fungus and diseases. They will get spots on leaves, loose leaves and not be perfect. Less than perfect plants is not a testament to your lack of care or ability. It shows learning in process.
Insect damage is a concern as it can kill a plant and spread to other plants. Inside in a building infestations must be dealt with as the insect’s life cycles are continuous. Outside some pests will have one cycle a year but others like aphids will disappear with a good frost.
Typically, insect damage appears in the form of holes in leaves, molted coloured leaves or large brown or clear spots.
Holes in leaves on the edges or in the centre are made by adult insects or caterpillars with chewing mouth parts. Given enough of these insects or caterpillars and they can defoliate a plant. Plants with strong root systems, with the exception of evergreens, will leaf out again once the insect passes into the next stage of its life cycle. Healthy plants can withstand a few years of being totally defoliated before they begin to look stressed or die.
Green leaves with yellow splotches or large clear or brown spots between the veins can be caused by a sucking insect. Some insects will feed in one spot and move to another leaving areas of the leaf lacking.
Others will burrow into the leaf or attach themselves firmly to the leaf sucking out the juices. These pests tend to be small, hard to see and harder to eradicate.
Bacteria, insects and caterpillars can enter a tree and feed on phloem or xylem cells under the bark. Sap oozing from the bark, dead leaves, bare branches and misshapen branches are all signs that the plant is diseased or there is internal insect damage. The life expectancy of an infested tree depends on what it is infested with.
Removing the damaged area andeither burning it immediately or double bagging it and placing it in the garbage will stop the problem from spreading.
Mildew starts as a white tinge to the foliage and progresses to killing the leaf. Removing all infected materials and improving the air circulation around infected plants by thinning foliage will help diminish the problem.
Typically, most cosmetic damage to plants, brown spots, or dead leaves are caused by environmental problems; the amount of water or sunlight.
Knowing, and fulfilling the plant’s environmental requirements makes for a healthier plant. Plants that are placed in too bright of light will get burnt leaves. When receiving too low of light the plant will put out fewer, smaller leaves.
Watering is the main issue with all plants. Too little, and the plants wilt. Some leaves will recover, others will not. Too much water causes the roots to rot and the top of the plant starves.
Best practice is to water the plant well, five cm, and less often, developing deep rooted plants. Water should flow through the soil and out the holes in potted plants. Water when the soil below the surface is dry to the touch.
As plant owners remember that plants are part of nature. Each one does not have to be perfect.
Linda Tomlinson is a horticulturist that has gardened in Central Alberta for over 30 years.