Ground cover is the glue that holds the garden together, the mortar between the bricks, the landscaping texture you'd plant under trees and shrubs.
In other words, it is the creative alternative to grass.
Gardening contributor Charlie Dimmock visits New York City to talk about it on The Early Show. But first she takes us to the Royal Horticultural Society's Gardens at Wisley for some inspiration.
The following are her favorite ground cover plants and her tips to prevent weeds from growing:
We'd all love to reduce the amount of work we have to do in the garden, especially when it comes to weeding, and one of the best ways to do that is to use ground cover plants. They grow over the soil and cut the sunlight out, which stops all the weeds from coming up.
The other reason for using ground cover plants is to unify ornamental plantings. The persicaria with its pink flower spikes and broad green foliage pulls together the whole area and makes it one.
When choosing your plants, you must consider the type of garden you have, whether it's very sunny, or very shady. In a shady area, you're going to be using plants like pulminaria, hosta, epimidium to create a very woodlandy effect.
In a shady area, you are going to be using plants like pulmonaria, ajuga, hosta and epimedium, which creates a woodsy effect.
If your garden's a much more open one, the ground cover plants you'll be using are things like lamb's tongue, with its really soft foliage followed by pink flowers in the summer; creeping ceanothis with its intense blue flowers; juniper blue carpet with foliage; and heuchera, which comes in lots of different purple foliage colors, and looks fantastic when you grow it with silver foliage plants.
If you grow bulbs, once the flowers start to die off, you'll find that you get a really scruffy effect. But if you try doing it through ground cover, you get a very stunning effect, and the foliage of the ground cover will grow up and cover all the dead leaves and flowers.
Now, if you're not sure about the conditions in your garden, then try growing ajuga or pachysandra. This is a variety form of pachysandra, and they both like sun and shade. They also like a drop of rain, which is what we're getting at the moment.
Here's the best way to create a weed-free garden:
Prepare well with a weed suppressant cloth between plants like heuchera and lamb's tongue. It lets the water in, but keeps whatever weeds are underneath from seeing the sun.
Put gravel or slate or bark over it to hide the cloth. Plant the ground cover at 2/3 the normal distance you would between plants, so once mature the plants overlap by one third.
Shrubs that work as ground cover are lavender, juniper, creeping ceanothus and cotoneaster.