To keep your garden perennials looking their best, you need to control weeds. Weeds rob the soil of nutrients that your flowers could be using. Controlling weeds in your flower beds isn’t difficult. Like flowers, weeds come in two main groups — annuals and perennials:

  • The annuals form staggering quantities of seed; some produce up to 500,000 per plant. Pull annuals out of your garden before they form seed.

  • Perennial weeds are harder to control. They seem to live forever and expand by sending out roots or running stems for several feet in every direction. These weeds want to conquer the world. Pulling and digging at them appears to make them mad; they seem to spread even faster in response. Perennial weeds also form seeds, so don’t ever let them get to this stage. Unfortunately, mulch doesn’t stop their roots or runners. The most effective way to dispatch perennial weeds is with an herbicide.

Practice good housekeeping habits in your garden. Remove dead and diseased leaves and stems promptly to get diseases out of the garden before they spread. Keep the flower bed clear of weeds, which may play host to diseases or insects. Clean and disinfect pruning shears and scissors (dip them in a solution of household bleach and water) after cutting diseased plants. If you smoke, wash your hands before gardening — tobacco can contain viruses that infect flowers.

When perennial weeds pop up in an established flower border, getting the herbicide on the weed but not the flowers is a challenge. Use a plastic bag to isolate the weed. Here’s how:

  1. Cut a hole large enough to fit the weed through in the bottom of a plastic bag.

  2. Pull the entire weed through the hole in the bottom of the bag.

  3. Place a stone in the bottom of the bag to hold it in place.

  4. Carefully spray herbicide into the top of the bag.

    If you accidentally spray or spill some herbicide on adjoining flowers, immediately rinse them off with water.

  5. Seal the top of the bag with a twist-tie and leave the bag in place until the weed is dead.

If your soil is loose and crumbly, a light tug is probably all you need to yank out the most stubborn weed. But in dense soil, what usually happens is that you tug at the weed and the top comes off neatly in your hand. The roots happily grow a new top, and the next time you look, the weed is back, looking refreshed and smug! To kill most weeds, you must get the root. Here’s the simplest technique to do so:

  1. Slip the blade of your hand trowel into the ground straight down, next to the main root of the weed.

  2. Push the trowel blade firmly against the root to loosen it.

  3. Grab hold of the base of the leaves and pull.

    Most of the time, this action gets you the whole weed — roots and all.