Ames Kalm's St. John's Wort (Hypericum kalmianum 'Ames')
hy-PARE-ih-kum kal-mee-AY-num 'Ames'

Deciduous Perennial Shrub in the Hypericaceae Family
 

Hypericum kalmianum is a native North American shrub that is hardy in USDA Zones 4-8. It is found growing naturally in moist, open areas and along the edges of woodlands throughout the northeastern and north-central United States and eastern Canada.

This compact, deciduous shrub typically grows 2-3 feet tall and wide at maturity. Its key features include:

Foliage: The small, linear-shaped leaves are blue-green in color and have a slightly glaucous appearance. The foliage turns an attractive reddish-purple in fall.

Flowers: From midsummer to early fall, Hypericum kalmianum produces an abundance of bright yellow, 5-petaled flowers. These blooms are about 1-2 inches wide and add a cheery pop of color.

Growth Habit: With a rounded, spreading growth habit, Kalm's St. John's Wort forms a dense, well-branched shrub. It spreads slowly by suckers to form colonies.

Cultural Needs: This native shrub prefers full sun to partial shade and moist, well-drained acidic soils. It is drought-tolerant once established.

Landscape Uses: Hypericum kalmianum makes an excellent addition to native plant gardens, woodland edges, or foundation plantings. Its compact size makes it suitable for smaller landscapes.

Wildlife Value: The nectar-rich flowers provide an important food source for pollinators like bees and butterflies. The foliage also serves as a larval host for certain moth species.

Overall, Kalm's St. John's Wort is a hardy, low-maintenance shrub that offers season-long interest and valuable ecological benefits in the garden.
 

Plant Data

Mature Size 24 - 36 inches tall. 24 - 36 inches wide.
Sun Exposure Partial Shade - Full Sun
Moisture Tolerance Medium
Zones 4a - 7b (Usually hardy to -30° F)
Tags Deciduous, Fragrant Flowers, Full Sun, Medium, Medium, Nativar, Partial Shade, Partial Sun, Perennial, Rabbit Resistant
Bloom Period July to August
Flower Color Yellow
 

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Pricing and Availability History

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Limited Availability

We try very hard to source exactly what you’d like, but sometimes growers run out of plants! While this variety is a great deal at the price shown, we know that it has limited availability. If you want the plant even if it might be more expensive, or in a different size or quantity -- after you place your order, just send us a quick note at help@northshoreplantclub.com. Then, we’ll try to get you some version of this from one of our growers. And if we can’t get it from anywhere, of course, we’ll send a refund!


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.

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