Astilbe plants are characterized by their tall, showy flowers that grow in the middle of rich, dark green foliage. The flower clusters of these shade perennial flowers can grow as tall as five feet, depending on the variety, and as little as six inches. Astilbe grows in a variety of colors. Bright pinks, deep reds and pure white flowers will grow depending on what variety of plant you purchase - astilbe is sure to brighten the dark spots in your garden. Even though the plant may look gentle, they are tough perennials that can withstand a variety of temperatures and climates, making then one of the best perennial flowers to plant in your garden. Once you plant them, they will have a long life if taken care of and properly nurtured.