Alert New York Aster (Symphyotrichum novi-belgii 'Alert')
sim-fee-oh-TRIK-um no-vee-BEL-jee-eye 'Alert'

Deciduous Perennial in the Asteraceae Family
A compact New York Aster with vivid crimson-red, yellow-centered blooms that light up the late-season garden from September into October.
'Alert' is a compact cultivar of New York Aster (Symphyotrichum novi-belgii, syn. Symphyotrichum novi-belgii) prized for its vivid deep crimson-red, daisy-form flowers with bright yellow centers. Blooming from September into October, it provides strong late-season color when many other perennials have finished for the year. The plant forms a tidy, upright clump of smooth, lance-shaped green leaves reaching 12 to 15 inches tall and wide, making it well suited to the front of a border or a container. Pinching back new growth in spring and early summer encourages a more compact, floriferous habit, and mulching helps keep its shallow root system cool through summer heat. Like other New York Asters, it attracts butterflies and other late-season pollinators.

Pros

  • Vibrant late-season color and pollinator joy when other plants are fading
  • Variety of sizes and colors
  • Several native Asters are available
  • Cold-hardy and reliable in Chicagoland

Cons

  • Can become leggy and flop over in formal gardens without regular pruning or early-season pinching back
  • Short bloom window
  • Needs full sun
  • Some types can self-seed aggressively
 

Plant Data

Mature Size 12 - 15 inches tall. 12 - 15 inches wide.
Sun Exposure Partial Shade - Full Sun
Moisture Tolerance Dry - Medium
Zones 4a - 7b (Usually hardy to -30° F)
Tags Attracts Bees, Attracts Beneficial Insects, Attracts Butterflies, Attracts Pollinators, Attracts Wildlife, Container, Deciduous, Deer Resistant, Dry, Fall Color, Fall interest, Full Sun, Good for Borders, Good for Cut Flowers, Low Maintenance, Medium, Native to North America, Partial Shade, Partial Sun, Perennial, Popular For Fall
Bloom Period September to October
Flower Color Crimson-Red, Yellow Center
 

In The News

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Pricing and Availability History

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Past Availability
2025 : 04/13 - 10/04
2024 : 05/01 - 10/05
2023 : 05/04 - 08/27

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Field-Grown vs. Greenhouse-Grown Plants

Plants which are well-adapted to our local climate are most often field-grown (outside). Field-grown plants are generally cheaper and have the advantage of already somewhat acclimated to our cold winters, but that means they’re not artificially far along in the spring and tend to bloom at the normal time in our area.

Spring annuals and tender perennials are typically grown in Greenhouses so they can be ready and luxurious exactly when customers want them. Some perennials are also “forced” into early bloom in greenhouses. In May, there can be a very big difference between field-grown and greenhouse-grown plants of the same type. The latter typically look good right away (so they’re a great choice where that’s important), but we typically pay a premium for it.


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No Pricing or Availability Right Now

We order from a rotating cast of the best nurseries in the Great Lakes region. It looks like we've offered this plant in the past, but the nurseries we're working with this week don't appear to have it in stock at the moment.

Our goal is to bring as many plants together under "one roof" as possible, so we'll try hard to make it available again in the future!