Collin County Master Gardeners

Common Gardening Mistakes

Choosing plants that are unsuitable for North Central Texas
There's a reason you hear Master Gardeners and other experienced plant people go on and on about native plants and/or well-adapted plants: those plants thrive here. Gardeners in Texas need to understand that we are in a very unique part of the United States - our weather and soil conditions make it a little tougher to grow certain things. But that doesn't mean your choices are limited or boring. And sometimes just a good layer of mulch makes all the difference.

Check out the excellent Texas Smartscape plant database to browse through good plant choices for our area.

Placing plants in an unsuitable location
Pay attention to the sunlight recommendations for plants. If the information tag recommends shade, don't put the plant in full sun. In fact, here in Texas we sometimes need to dial down sunlight recommendations because of our intense summer heat and sunlight. Most plants that are described as needing full sun will do just fine out in the open all day, however.

The same goes for moisture levels - don't place moisture-loving plants in an area that stays dry most of the time, and vice versa. Also pay attention to wind exposure, and microclimates. Regarding the latter, if you plant up against a brick wall, that brick will absorb a lot of heat during the day. Make sure any plants you place near the wall are heat-tolerant.

Improper watering techniques
This is a biggee. Many gardeners water too frequently and too shallow. The proper way to water is infrequently, but deeply.

If you have an automated sprinkler system for your landscape, place shallow, straight-edged cans (like a tuna can) throughout your yard and run the sprinklers to determine how long it takes the system to provide 1" of water. If you find it takes 20 minutes per station to provide 1", run the system for two successive cycles of 10 minutes each, preferably in the early morning hours, once a week. Running two cycles allows the water to soak in better.

Overfertilizing
In the case of fertilizers, more doesn't mean better. Overuse of synthetic fertilizers is especially dangerous because it can "burn" plants. It can also result in unnatural growth spurts which can in turn attract more pests and diseases.

More importantly, however, is the toxic runoff that results from watering excessively-fertilized plants and lawns. This runoff is called "non-point source pollution" because the pollutant cannot be tracked back to one single source. When large amounts of nitrogen and phosphorus are present in local streams, algae blooms are created that can destroy ecosystems. When algae starts dying, it uses up the oxygen and kills off the aquatic organisms.

Carefully follow application instructions provided on fertilizer containers. Better yet, compost your grass clippings, leaves and yarm trimmings, and use the compost as your fertilizer.

Excessive pesticide use
The first thing many gardeners do after seeing insects on plants is reach for the spray. Gardeners should instead ask themselves a few questions:

What kind of bug is it? Is it harmful to the plant or not?
If the insect is considered a pest, does it warrant spraying? Is there an infestation on the plant or just one isolated bug? Is it actually doing damage or just hanging out?
Are there birds, beneficial insects or spiders in the immediate vicinity that might either a) take care of the pest problem themselves or b) be harmed as a result of spraying a pesticide?
If a pest infestation is present, is there an underlying reason why? Check soil, moisture and light conditions. Pests will usually attack an already weak plant.

Learn to tolerate a few bad bugs. If it weren't for them, many birds, spiders and beneficial insects wouldn't have anything to eat. If you do decide to apply a pesticide, always start with the least toxic, and apply it in the early evening after honeybees have left the area. Always follow label instructions. This applies to fungicides and herbicides as well.

Failing to adequately prepare the soil for planting
Just like the weather, the soil here in Collin County is tough, literally. In most areas of the county it is a dark, sticky clay, often referred to as "Black Gumbo". Very difficult to dig in, and somewhat hard for plants to grow in. While the nutrient levels are generally ok, oxygen levels are low due to clay soil's density. Water tends to run off when clay soil is dry. Lastly, our clay soils lean toward the alkaline side, which some plants don't like.

Most of all, it is very important that before planting, gardeners should amend the soil with copious amounts of organic matter. Compost and finely chopped leaves are excellent additives. A somewhat new product called expanded shale has also proven helpful when mixed with compost in loosening clay soils. (A little bit of patience also helps, as clay soils will not improve overnight.)

Finally, never, ever work in clay soils when they're wet - it creates a huge mess and depletes the oxygen levels even more. Don't even try to till in it. And, despite what some folks may recommend, don't add sand to clay soils.

Spacing issues
Although the glossy magazine pictures of gardens jam-packed with plants are pretty, cramming plants together can cause all kinds of problems. Moisture and nutrient levels are depleted and air circulation declines. Plants and seeds usually come with spacing instructions, so try to follow them. When in doubt, leave more space in between plants rather than less.

Wrong planting depth
Most plants benefit from being positioned so the crown is slightly above the soil surface. This also allows for eventual soil settling. Trees should be planted so that the root flare is generously exposed - avoid the 'telephone pole' look!

Improper pruning techniques
Cutting off too much of any plant can result in death. Not cutting back at all can limit blooming. Trimming at the wrong time can expose some plants to pest and diseases. So, what's the happy medium? Read on:

Bad timing of planting
Spring flowering bulbs should be planted around Thanksgiving in our area. Ditto for wildflower seeds. Most trees and shrubs will do best if they're planted during their winter dormancy. Perennials benefit from fall planting, thus giving them a chance to establish roots before winter. If you're a vegetable gardener, learn which veggies are considered "cool weather" crops and stick to planting them at the proper time.

Planting invasive species
Did you know that the popular pincushion flower (Scabiosa atropurpurea L.) is considered an invasive species here in Collin County?

Some others on the list may surprise you. Check out TexasInvasives.org for more information about local invasive plants.

Planting poisonous species
If you have curious children or pets, avoid planting anything that could potentially be touched or eaten that could cause harm.