DIY Network

Once weeds become established, many can adapt to their changing environments so fixing the problem won't necessarily kill them off. You need to remove them and do it carefully so they won't spread. Make sure to get all of the seeds or tubers -- anything they can reproduce with. Yellow nutsedge is particularly difficult to remove because each tuber will sprout a new plant; it's very aggressive in the right environment.

To amend the problem, you'll need to fix your drainage. There are a lot of plants that don't like soggy soil, so if you can get that water to drain away, they'll start looking better. Check your drainage system to make sure it's not clogged and amend your soil so water flows through it better. Fixing the problem may even be as easy as cutting down on watering.

	Annual bluegrass
	Bermuda grass

Problem No. 2: Compacted soil

Another problem that will keep plants from looking their best is compacted soil — soil that doesn't leave any room for air. Lots of garden plants need room to spread their roots and benefit from a little air in the soil, so your soil could be smothering them. Some cultivated plants don't have strong enough roots to penetrate through compacted soil, but there are some weeds that don't mind growing in a tight squeeze. Here are two common weeds found in compact soil:

The good thing about having weeds growing in compacted soil is that removing them actually helps to amend the problem. Their strong roots break apart the soil for you and pulling them adds air and breaks the soil apart even more.

Cultivate and amend heavy clay soil with compost. If your lawn has weeds, aerate it. An aerator tool will pull out small pieces of the lawn, introducing air into the soil.

English ivy and violets

Problem No. 3: Not enough sun

Your plants may not be doing well because they're simply not getting enough sun. If you see these shade-loving weeds next to your geraniums, for example, you've found your problem:

One key thing to remember in this case is: Weeds aren't always the enemy. Some shady-site weeds are actually attractive in the landscape but you want to make sure they don't take away from your other plants. Ground ivy is a very aggressive grower, but it won't crowd out other plants, so you can still enjoy the plants you selected for that area.

If you're not happy with the weeds, simply remove them and make adjustments to that area to allow more sunlight in. For example, thin out tree branches that are blocking the sun.

You may not be able to work around the shade problem, though. If it's an area that will always be in the shade for a good part of the day, transplant your sun lovers to a better spot and replace them with plants that are better suited for that environment. Hostas, ferns and coral bells are popular landscape plants that do well in shady areas.