Early last summer, I was working in the garden when a cousin called and wanted to bring a friend from Charlotte, N.C., an avid gardener, to visit my garden. I said come on; I am in the yard working. The two ladies arrived and before leaving the guest came over to tell me that she was amazed that I was not a "purest." She did not think that annuals belonged in a perennial border.

Well, I do have a colorful border of perennials that I love to work with each year, but I am always looking for new plants to add or to move things to a different place. Because I have a vole problem that Voltaire, my cat, cannot stay on top of, I add annuals to make sure I have exquisite flowers all summer long. Voles do not seem to be interested in the small roots of annuals.

I love to fill empty spaces with annuals. I think this is a good way to fill in the cracks. I was told once that soup fills in the cracks in your stomach (not sure about this), but that is the way I feel about adding annuals to the perennial border.

Gertrude Jekyll, the legendary British horticulturalist and designer of perennial borders, used to scatter nigella seeds in her Victorian clients’ gardens. I tend to add seeds to my border to make sure I have some color in the late summer when many of my plants have stopped blooming.

I add a package of white cosmos seeds in early June, anticipating that they will germinate soon and will be charming by August. These flowers add a little height to fill in where the daylilies have finished blooming. These lovely flowers sway in the breeze and grace the border. You can find cosmos seeds with different shaped petals and colors such as reddish-purple, white, yellow, and some are bicolored. There are some called "seashell" because of the way the petals are fluted. I like to get ones that are about 3 to 4 feet tall to give the bed some height.

Zinnias are another great easy to grow annual that brightens the border. Nothing completes a country bouquet like zinnias. The range of colors, shapes, and sizes to choose from is sizeable. There are small blooms, large blooms, double and single flowers as well as a variety of heights. Zinnias have vibrant colors, sturdy stems, and brighten up any border.

"Nicotiana alata" or Jasmine Tobacco is an annual that I discovered several years ago. I have white ones, which are fragrant in the still of the night, adding to the charm. These exotic looking flowers bring hummingbirds to your garden. I prefer the white ones but they also come in rose, deep purple, red, and pinkish colors. This is an annual that many people ask about when they see the trumpet-shaped blooms.

When you are planning what flowers to plant in your border, make sure you have some plants that will add some height and others that serve as "see through" plants. I learned this from my friend Jane Dempsey; having height in a border makes the bed look more impressive. As for the "see through" plants, these can be ones like cosmos, Gaura "Siskiyou Pink," or Verbena bonariensis to mention a few.

If you are starting out to design a bed for the first time, make sure you choose a site with at least six hours of sun and good soil. Both of these are essential. If you have a hard clay soil, you will need to add some organic compost. Clay has a lot of natural minerals in it’s soil, but it can become hard and adding composted leaves, ground bark or some organic amendment to the soil, will help your plants perform their best. A professional perennial grower told me that perennials love flowerbeds that have soil that resembles chocolate pudding. It should be very easy to dig into and a rich chocolate color.

When designing, remember that you can add some shrubs to the bed or as a backdrop. They make a great addition. My bed is narrow because of the location and I am not able to add shrubs behind the plants and I miss that aspect.

A garden is a highly personal work of art. Your taste, choice of colors, and design will differ from your best friend. Plus, no matter how hard your try to copy a border, it is difficult. The sun exposure, location of a nearby tree that takes up water, and the soil are not always exactly the same in different places. Get some ideas from others, then work to create your own work of art. It will give you great satisfaction.

Betty Montgomery is a master gardener and author of “Hydrangeas: How To Grow, Cultivate & Enjoy,” and “A Four-Season Southern Garden.” She can be reached at bmontgomery40@gmail.com.