Color Flash Astilbe will grow to be about 15 inches tall at maturity extending to 20 inches tall with the flowers, with a spread of 20 inches. When grown in masses or used as a bedding plant, individual plants should be spaced approximately 16 inches apart. Its foliage tends to remain dense right to the ground, not requiring facer plants in front. It grows at a medium rate, and under ideal conditions can be expected to live for approximately 10 years. As an herbaceous perennial, this plant will usually die back to the crown each winter, and will regrow from the base each spring. Be careful not to disturb the crown in late winter when it may not be readily seen!
This plant does best in partial shade to shade. It requires an evenly moist well-drained soil for optimal growth. It is very fussy about its soil conditions and must have rich, acidic soils to ensure success, and is subject to chlorosis (yellowing) of the foliage in alkaline soils. It is somewhat tolerant of urban pollution, and will benefit from being planted in a relatively sheltered location. Consider applying a thick mulch around the root zone over the growing season to conserve soil moisture. This particular variety is an interspecific hybrid. It can be propagated by division; however, as a cultivated variety, be aware that it may be subject to certain restrictions or prohibitions on propagation.
Color Flash Astilbe is a fine choice for the garden, but it is also a good selection for planting in outdoor pots and containers. With its upright habit of growth, it is best suited for use as a 'thriller' in the 'spiller-thriller-filler' container combination; plant it near the center of the pot, surrounded by smaller plants and those that spill over the edges. Note that when growing plants in outdoor containers and baskets, they may require more frequent waterings than they would in the yard or garden.
