1. Underestimating a plant's mature size
We typically plant much smaller plants than their fully grown size, for practical and economical reasons. If you don’t pay attention to the expected height and width and growth rate of a plant, it may not work out in the spot you plant it. Allow plenty of space between plants and structures, especially for fast growing plants. If you are spacing closer than recommended, plan to trim or prune regularly, before it gets out of control.
2. Pruning flower buds at the wrong time
Flowering trees and shrubs need to be pruned at the right time or you risk cutting off the next season’s growth. If they flower in Spring, only prune right after flowering. If they flower in the summer, most can be pruned in Spring.
3. Not watering enough
You may be surprised how much water plants need, especially if they are newly planted, have shallow roots, are in sandy soil, or if the weather is extra hot, dry, or windy. The best way to know is to stick your finger a couple inches into the soil and see if it is wet or dry.
4. Watering too much
You can have too much water, although this is more common in pots than in the ground. If you have an area that doesn’t drain well or you get extreme amounts of rain the roots can’t get enough oxygen, and it will rot and damage or even kill the plant.
5. Misusing chemical fertilizers or herbicides
Synthetic fertilizers and herbicides can burn or even kill plants if used improperly. Using the wrong spray, mixing it too strong, or spraying at the wrong time can cause problems. Using too much or too strong fertilizer can burn plants or grass. The best way to avoid these problems is to use natural organic fertilizers and manual weed control when possible.
6. Volcano Mulching
When mulch is mounded up around a tree in the shape of an upside-down funnel, this is called volcano mulching. This is bad for the tree because it can rot the bark, decrease oxygen to the crown and roots, and it also makes a nice place for rodents to live. Keep mulch a few inches away from trunks and don’t apply more than 4 inches deep. This applies to shrubs and perennials as well. They can be damaged by too much mulch piled up around the stems.
7. Cutting back bulbs too soon
It’s tempting to remove the foliage from bulbs that are done flowering, but it can be harmful to the plant. The foliage need to be exposed to sunlight to recharge the bulb for next year. If you cut back, tie up, or cover the leaves, you can sabotage next year’s floral display. Wait until leaves are yellow or brown. Better yet, use later emerging plants around the bulbs to block the view of the yellowing foliage if it bothers you.
8. Giving up on plants too soon
If you are new to growing certain plants, you may think they are dead if you don’t see leaves emerging right away in Spring. Some plants just stay dormant longer than others, and if you cut back or dig them up too soon, you may be getting rid of a perfectly good plant. If you are unfamiliar with what is normal for a certain plant, wait until late May or early June before declaring them dead. You can also check woody plants for green by scraping a tiny bit of bark.
9. Planting too soon
It can be hard to resist all the lovely plants filling up the Garden Centers in April, but if you plant them too soon, you may regret it. In our area, it is common to get frost up until late April, and we usually recommend waiting until mid-May to put in tender plants. Also, many plants in the garden centers have been brought in from more southern states or greenhouses, and have not been acclimated to our climate.
10. Ignoring hardiness zones
Another common mistake is buying plants that are not hardy to our area. We usually recommend plants that are rated for Zone 4 or less. There are many plants in local garden centers that are Zone 5, and they may survive in a more protected spot, but they may be damaged in harsh winters. Sometimes these not-quite-hardy plants can be treated like perennials, dying back and regrowing from the roots. If you want to try more exotic plants in your garden, they need to be more protected, or even brought inside over winter.
