Annual Flowers for Root Bound Areas
The areas under trees are often full of tree roots. Some of those roots are close to the top of the soil, making the area root bound. Digging up the area can injure these roots and damage the tree. Annual flowers are ideal for planting in root bound areas because you can plant them by seed, or in small holes for six-packs of seedlings. Annuals are shallow rooted, so won't disturb the roots of the trees.
In warm-winter climates, U.S. Department of Agriculture plant hardiness zones 8 through 10, spring begins as early as December. If the area is root bound but in a sunny location, cool-season flowers work well. Consider the seasons. The area could be in shade during the summer but in full sun during the spring because it's under deciduous trees. Cool-season annual flowers include Lobelia (Lobelia inflata) which grows to from 6 to 30 inches high and is covered with tiny blossoms in pale blue or white. Calendula (Calendula officinalis) has bright orange and yellow daisy-shaped flowers from 3 to 4 inches across. The flowers are edible. The bush grows to 18 inches high. Sweet peas (Lathyrus odoratus) usually grow from 5 to 6 feet high and need a support for their tendrils to grasp. However, there is a dwarf variety that only grows to 18 inches and doesn't need a support. Other spring selections include stock (Matthiola incana), pansies (Viola x wittrockiana) and snapdragons (Antirrhinum majus).
Summer gives you a wide variety of flowers from amaranthus (Amaranthus) to zinnias (Zinnia elegans). When the spring flowers are fading, pull them out. Pulling up the plants will make the area a bit uneven. Gently rake the area smooth with a grass rake so you don't disturb the tree roots. Plant the seeds of the summer annuals. Amaranthus have purple, red, pink or yellow flowers. The flowers may form little fuzzy balls or be tufted on upward spikes. Zinnias have a range of colors, all except blue; sizes -- from 1/4 to 4 inches in diameter and grow from 6 inches to 36 inches high. Other summer annual flowers include cosmos (Cosmos bipinnatus), growing up to 48 inches high, and marigolds (Tagetes patula).
Trees such as oaks don't do well with regular watering during the summer, especially in Mediterranean climates where oak trees have adapted to summers that don't get much rain. Plant drought-resistant annual flowers underneath the oaks. Love-in-a-mist (Nigella damascena), verbena (Verbena), moss rose (Portulaca grandiflora) and bachelor button (Centaurea cyanus) are all drought resistant.
Preparation and Planting
Before planting, soak the area so it's wet to a depth of 6 inches. Test it out by plunging a screwdriver into the soil. Let the area dry off a bit so you're not planting in mud, but rather damp soil. How long that takes depends on the weather. In foggy coastal areas it could take up to a week. In dry inland locations, the soil could be ready the next day. Scatter the seeds and cover with no more than 1/2 inch of soil. The exception would be large seeds, such as sweet peas; poke a hole in the soil 1 inch deep, slip the seed in the hole and cover. Water with fertilizer that is water soluble to soak the bed.
- University of New Hampshire: Landscaping With Flowers
- Sunset Western Garden Book; Editor Kathleen Norris Brenzel
- The Country Garden; Charlie Ryrie
Katie Jensen's first book was published in 2000. Since then she has written additional books as well as screenplays, website content and e-books. Rosehill holds a Master of Business Administration from Arizona State University. Her articles specialize in business and personal finance. Her passion includes cooking, eating and writing about food.