Some easy and fast-growing plants are Knock Out rose bushes, common marigold, spider plants and Confederate roses. Calendula and heavenly bamboo are also low-maintenance plants.
Calendula, or pot marigolds, grow up to 30 inches tall in one growing season with 3-inch flowers ranging from yellow to orange in color. Place the plants in an area with plenty of sunlight, and water them when the soil starts to dry out.
Common marigolds, which are unrelated to pot marigolds, grow up to 4 feet high and 12 inches wide. They only require regular sunlight and regular water.
Knock Out roses not only grow to 3 feet tall, they are also pest resistant, drought tolerant and cold hardy. They only need to be pruned regularly to the desired size.
The Confederate rose bush can reach up to 15 feet high. Water it regularly in hot, dry weather, and add 2 to 4 inches of pine needle or bark mulch to keep the soil moist.
Heavenly bamboo grows tall and spreads outward quickly, although shorter dwarf cultivars are available. In fact, this fast-growing plant is considered invasive if left to grow on its own. Plant heavenly bamboo in full sun for the brightest foliage, and water it regularly.
The spider plant is primarily a houseplant that can reach up to 16 inches tall and requires very little water and indirect light.