Flowers add colorful burst of beauty in landscapes. Although blossoming plants look nice in flowerbeds and border plantings, they also create interest in containers and boxes. Flower boxes enhance the edges of patios and porches, as well as areas around mailboxes, gazebos and swimming pools. Like other types of container plantings, flower boxes minimize the need for continual weeding. Plant a few flower boxes to add enjoyment to individual areas of your yard and landscape.
Select flowers suitable for your flower boxes. The space inside flower boxes limits your selection of plants to those that maintain small to medium sizes. Select varieties of flowers that flourish in containers, such as geraniums, petunias, pansies and marigolds. Include flowering vines and ground covers that drape and flow over the edges of your flower boxes. The spreading characteristics of sweet peas, sweet alyssum and morning glories dress up the outside edges of your flower boxes by extending over the edges.
Cover the bottom on the inside of your flower boxes with a layer of gravel. Use clean gravel that does not contain weed seeds, automotive oils or other contaminants. Spread about 1 inch of this gravel in your flower boxes to help water drain away from your plants' roots.
Place a layer of potting soil over the gravel. Make the layer deep enough to allow adequate room to place your flowers' root balls on top of the soil with their surfaces just below the rim of your flower box. The depth of this layer depends on the depth of your flower boxes. Practice the placement of your selected varieties by keeping them in their pots, while placing them on top of the layer of soil. Place your taller varieties near the back edge of your flower box and the shorter plants and vines near the front. Experiment with different patterns by moving your potted plants around, finding the best balance between sizes and colors. This practice run will also allow you to see how much soil you need in your bottom layer to keep the surface of your flowers' root balls just below the rim of the container.
Remove your flowering plants from their containers. Set them on the surface of the soil in their permanent locations. Allow adequate space between each plant for mature growth and airflow. Fill in the areas between the root balls with potting soil. Use a small hand shovel to sprinkle the soil into all the gaps and spaces. Gently firm the top of the loose soil with your fingertips to create a level surface. Slowly water your new plants until you see drops coming from the drainage holes on the bottoms of your flower boxes.