Blue wood aster (Symphyotrichum cordifolium)
Blue wood aster is native to woodland edges in central and eastern North America, and grows happily in full sun to part shade. If they are growing in shade, plants will need at least 3 hours of sunlight a day for the best flower show. This aster is a prolific bloomer as you can see in the photo above and pollinators love all those blooms. Its pale blue (or sometimes deep blue) flowers with yellow centers start opening in late summer and last until midfall.
Blue wood aster grows best with regular moisture during dry periods but doesn’t like wet feet. Water plants at soil level and allow space between plants so air can circulate in order to prevent fungal disease that can mar the foliage. At up to 5 feet tall, it's not uncommon for blue wood aster to flop, so you’ll likely need a stake or two to keep the flowers upright. Use a half hoop stake or a grow through stake to give plants some extra support.
- Type Perennial
- Light Full sun to part shade
- Soil Moist, well-drained
- Size 24 to 60 in. tall, 18 to 24 in. wide
- Cold hardiness USDA zones 3 to 8
Adding blue wood aster to your garden
Blue wood aster spreads easily by rhizome and reseeding, which makes it a good choice for the cottage garden or a meadow filled with vigorous growing companions that can hold their own (and help hold the leaning aster stems up). ‘Avondale’ is a popular variety that’s easy to find at garden centers or online nurseries. It’s more compact and even more floriferous than its wild cousin. It grows 24 to 36 inches tall and 18 to 24 inches wide in zones 3 to 9.