White Wood Aster

Year-round

White wood aster is an easy, spreading shade plant with small white flowers in late summer and fall. It likes part shade and medium to dry, well-drained soil. It is hardy in zones 3 to 8 and listed as deer resistant.

• Part shade is best, with about 3 to 4 hours of sun.
• Drought tolerant once established.
• Spreads by rhizomes, so give it room or divide often.
• Powdery mildew can show up, so give it air.

Fall

Fall is bloom time, with white flowers from about August to October.

• Enjoy the flowers and leave them up.
• Water if the fall is very dry.
• Do not shear now.
• Divide only after bloom, if at all.

Winter

In winter it is dormant. Leave the stems until late winter.

• Leave stems standing for winter looks.
• Cut back in late winter.
• Do not fertilize.
• Check drainage so water does not sit on roots.

Spring

Spring is the time to divide, pass along extras and set the plant up for summer.

• Divide clumps in spring.
• Pull out runners where you do not want it.
• Water new divisions weekly.
• Skip heavy fertilizer.

It can spread, so edge it from tidy lawn lines to stay HOA-friendly.

Summer

A shearing to about 6 inches in early summer makes a fuller plant. After that it needs little.

• Shear to about 6 inches in early summer.
• Water new plants in dry spells.
• Space plants for air flow to cut mildew.
• Avoid wetting leaves late in the day.

Year-round

White wood aster is a shade-friendly aster with white flowers in late summer and fall. It spreads slowly by underground stems and handles dry soil well.

• Give it part shade, about 3 to 4 hours of sun a day. Deep shade works too.
• Use medium to dry, well-drained soil.
• It grows 1 to 3 feet tall and 1.5 to 2.5 feet wide.
• Deer tend to leave it alone, says NC State.
• Powdery mildew can show up, so give it airflow and drainage.

Fall

August to October is bloom time with white flowers. Let them finish.

• Water new plants during dry autumn spells.
• Enjoy flowers through October.
• Leave seed heads for birds and small animals, says NC State.
• Fall planting works well in Harrisburg.

Winter

The plant is dormant in winter and needs nothing from you.

• No watering needed when the ground is frozen.
• Leave leaf litter in place as natural mulch.
• Cut back old stems in late winter if you want a clean look.
• Plan spring divisions now.

Spring

Spring is the time to divide or move clumps, since it spreads by underground stems.

• Divide crowded clumps in spring.
• Water new divisions until they settle in.
• Avoid planting in heavy clay that stays wet. Aster wilt likes poor drainage.
• Clear last year's leaves gently from the crowns.

Summer

In early summer you can shear the plant to about 6 inches for a more compact shape.

• Shear to about 6 inches in early summer if you want fuller, shorter plants.
• Water new plants in dry weeks. Established plants handle drought.
• Watch for white powdery mildew on leaves.
• Space plants so air can move between them.

Early summer shearing keeps the plant compact and neat for beds near the street.

Year-round

White wood aster wants shade to part shade, soil that stays lightly moist but drains well, and room to spread into a low groundcover clump about one to two and a half feet tall.

• Plant it in shade to part shade. It also tolerates deep shade under trees, more than most garden plants can handle.
• Keep the soil average to consistently moist and well drained. Once it is established it can handle short dry spells.
• Add two to three inches of mulch and keep it topped up. That holds moisture and keeps roots cooler through Tallahassee's long hot summers.
• It spreads slowly by underground stems into a groundcover clump one to two and a half feet tall and about as wide. Give it room or plan to divide it every few years.
• This aster's documented native range is the Appalachian mountains, the Piedmont, and the Northeast. It is not listed as native to north Florida, so in the Tallahassee area it is best thought of as a shade garden plant rather than a native planting.

Fall

Fall is bloom season and the easiest stretch of the year for this plant in the Tallahassee area, with small white flowers opening as the heat breaks.

• Small white daisy-like flowers open from late summer into fall and can keep blooming into November here.
• Deadheading is optional. Leaving the spent flowers lets seed form, which birds will eat over fall and winter.
• Cooler, less humid fall weather is easier on this plant than summer. Cut back on watering as temperatures drop.
• The average first frost in the Tallahassee area lands in mid November, so expect foliage to start fading and dying back around then.

The white fall flowers read as tidy and intentional in a front shade bed, which supports an HOA-friendly look during bloom season.

Winter

Winter is mostly a resting period here. Foliage dies back after frost and the plant needs little care until spring.

• Once the foliage turns brown after frost, cut the dead stems back to a few inches from the ground.
• Keep mulch in place over winter. It buffers the crown during Tallahassee's occasional hard freezes, which typically drop into the low twenties Fahrenheit.
• The plant is dormant now and needs little to no extra water unless the winter turns unusually dry.
• With the bed cleared out, winter is a good time to map where you want to move divisions once spring growth starts.

Cutting back the dead stems keeps a front-facing shade bed looking tended through winter instead of leggy, which is part of an HOA-friendly look.

Spring

Spring is when new leafy growth returns, and it is the best time to divide the clump or refresh mulch before summer heat sets in.

• New leaves come up from the base a few weeks after the last frost, which averages around mid March in the Tallahassee area.
• Refresh the mulch layer now so it is in place before summer heat and humidity arrive.
• If the clump has spread past where you want it, divide it in early spring while the new shoots are still short.
• Spring rain is usually enough on its own. Water only if the soil goes dry for several days in a row.

Summer

Summer is the hardest season here since Tallahassee's heat and humidity sit right at the edge of what this plant normally handles, so shade and steady moisture matter most.

• Give it the shadiest, coolest spot you have. Tallahassee summers push past the top of this aster's usual hardiness range, so full shade helps it cope with the heat.
• Watch the leaves for a white powdery coating. This aster can develop powdery mildew in humid weather, and giving plants room for air to move around them helps prevent it.
• Summer thunderstorms usually keep the soil moist enough. During a dry stretch of a week or more, water at the base of the plant instead of overhead so the leaves dry faster.
• Hold off on fertilizer during peak summer heat. It is not needed for an established plant and can encourage weak growth at the worst time.

Year-round

White wood aster is a shade-loving perennial that grows 1 to 3 feet tall and blooms late summer to fall. It prefers well-drained soil, which matters on Chattanooga clay.

• Give it part shade, about 3 to 4 hours of sun, and well-drained soil.
• It tolerates clay and rocky soil, but poorly drained clay can cause aster wilt.
• It spreads by underground stems and reaches full size in 2 to 5 years.
• NC State lists it as deer resistant and low maintenance.

It spreads on its own, so give it room or divide it now and then to keep the bed neat.

Fall

Fall is bloom time, roughly August through October, with small white daisy flowers. The seeds that follow feed birds and small mammals.

• Leave spent flowers so seeds can form for wildlife.
• Water only if the soil is bone dry.
• Fall is a good time to plant new ones in Chattanooga.
• Rake heavy leaf piles off the plants so they do not stay wet.

Winter

Winter is dormant time. It is hardy in zones 3 to 8, so Chattanooga winters are mild for it.

• No watering or feeding is needed.
• Leave the seed heads over winter for birds, then cut them back in late winter.
• Do not smother the crown with thick mulch.
• Plan any spring division now.

Cut old stems back in late winter so the bed looks tidy before spring growth.

Spring

Spring is the time to plant or divide. New growth comes up from the spreading roots as the Chattanooga soil warms.

• Divide crowded patches in spring and replant the pieces in part shade.
• Water new plants regularly for the first few weeks.
• Add a light layer of leaf mulch but keep it off the crowns.
• Check soil drainage before planting, since soggy clay invites aster wilt.

Summer

Summer is leafy growth before the late-season flowers. In Chattanooga's humid heat, airflow matters because it is somewhat prone to powdery mildew.

• In early summer, shear stems to about 6 inches if you want a more compact plant. NC State notes this.
• Space plants and thin crowded stems so air moves through.
• Water deeply during long dry spells, though it tolerates dry soil once established.
• Keep it out of hot afternoon sun in the open.