Amsonia Plant Care: How to Grow Blue Star Flowers

Amsonia plants—also called bluestar flowers or blue stars—are members of the Apocynaceae (or dogbane family) with light blue flowers, golden-yellow fall foliage, and milky sap. These wildflowers are herbaceous perennial plants, so under the right conditions, they will last at least a few years, if not much longer. The plants are native mainly to North America.

Amsonias’ initial bloom time takes place from early to late spring, although their trademark blue flowers might not begin to emerge until early summer. Mass plantings of amsonia plants prove to be excellent groundcover—their wide, bushy foliage provides a lot of shade to smaller growths. They’re also naturally attractive to pollinators like carpenter bees and hummingbirds.

There are countless versions of the basic amsonia plant. Here are just four key plant types to consider.

1. 1. Amsonia ‘Blue Ice’: This blue dogbane flower is shorter and stockier than many other types of amsonia. It’s a hybrid plant, but experts can only agree on one of its parents with certainty.
2. 2. Arkansas amsonia: Also called Hubricht’s bluestar, Amsonia hubrichtii sprouts threadleaf foliage and can withstand a wide array of climatic conditions. Its fall colors are particularly vibrant.
3. 3. Eastern bluestar: This bluestar is the most common variety of the plant and also goes by the names willowleaf and willow amsonia in addition to two scientific names, Amsonia tabernaemontana and Amsonia ciliata.
4. 4. Ozark bluestar: Amsonia illustris is most notable for its sparkling leaves, which explains one of its common names: shining bluestar.

Amsonias are low-maintenance plants, but they still need a little assistance to achieve their full potential. Follow these eight simple tips to help your amsonia plants thrive:

1. 1. Give them light. These plants do best when you provide them with some degree of partial shade, but they can withstand the rays of a full sun. Either way, make sure they get plenty of light to ensure they grow to the best of their abilities.
2. 2. Heed your climate. Amsonia plants are moderately drought-tolerant, but you should still keep their environments moist in particularly dry times. As for making it through the winter chill, they do best in US Department of Agriculture (USDA) Zones 3–7. Consult the USDA Hardiness Zone Map to discover whether amsonia will survive your region’s winter.
3. 3. Pay attention to spacing. Amsonia plants can branch out to around three feet wide, so do your best to space them out with that in mind. Otherwise, you run the risk of their foliage and root systems becoming tangled.
4. 4. Pick the right soil. A moist soil type provides the most suitable growing conditions for amsonia plants. Aim for a soil pH in the 6.0–7.0 range. A loam or clay soil will work so long as you ensure it’s both well-draining and never too dry.
5. 5. Provide food and water. Add mulch to the plants’ area to give them a boost and fertilize them at the start of their growing season, too. Provide them with water when their soil looks dry, but don’t add too much moisture to their environment. Waterlogging these plants can be just as damaging as not giving them enough water.
6. 6. Prune when appropriate. As your plants grow, you might need to prune down any dead foliage or just trim them in general. Blue dogbanes make good cut flowers if you’re looking for a reason to take off a little height.
7. 7. Take care of pests. While this plant is deer-resistant, it still has to deal with other pests. Hummingbird moths and their larvae especially like to feed on amsonia plants regularly. If the problem gets too out of hand, you can resort to an insecticide. Placing zapper lights around your garden may also come in handy.

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