Plant Visions in Red Astilbe in partial to full shade. Ensure the soil is consistently moist and well-draining. Space plants about 18-24 inches apart. Water regularly, especially during dry spells, to maintain soil moisture. Fertilize in early spring with a balanced, slow-release fertilizer. Deadhead spent flowers to encourage new blooms. Divide clumps every 3-4 years in early spring or late fall to maintain vigor.