How to Grow Astilbe in Pots
If you want to grow one plant, start with a container with a width of at least 16 inches and a depth of about 12 inches (30 cm.). If you want to grow more than one astilbe, look for a larger container. Fill the container with a good quality commercial potting mix, or create your own with a combination of organic material such as peat, compost, composted bark chips, perlite or sand. Be sure the container has at least one drainage hole. If you want to save yourself some time, purchase starter plants at a greenhouse or nursery. Astilbe seeds can be difficult to germinate, but if you want to try, plant the seeds directly in the pot, and then cover them lightly with potting mix. When the astilbe are 2 to 3 inches (5 to 7.6 cm.) tall, thin the plants to a distance of at least 6 to 8 inches (15 to 20 cm.) for small plants and 8 to 12 inches (20 to 30 cm.) for larger varieties. Avoid overcrowding, which can cause rot and fungal disease.
Caring for Potted Astilbe Plants
Astilbe thrives in light sunlight or moderate shade. Although astilbe grows in total shade, the blooms won’t be as vibrant. However, if you live in a hot climate, locate the plants in afternoon shade, as most types of astilbe won’t tolerate intense sun. Check the container often and water potted astilbe plants whenever the top one inch (2.5 cm.) of soil feels dry to the touch – which may be daily during the heat of summer. Be sure the pot drains well and never allow the soil to remain soggy. Potted astilbe plants benefit from application of a water-soluble fertilizer twice monthly, beginning with the appearance of new growth in spring and ending when the plant goes dormant in autumn. Divide container grown astilbe every three to four years.
