Grass pinks are a fun and rewarding species to cultivate. They're easy and adaptable and produce striking flowers in early summer. And, like the more common spring-flowering bulbs, they can be grown in pots and even "forced" so that you have flowers for an extended period of time.
In the wild, Calopogon tuberosus grows in open, wet, and somewhat acidic places, like bogs and wet meadows. If you have such accommodations, it should adapt just fine. In a garden setting, it needs consistent moisture, at least through the flowering period. Grass pinks can be grown in artificial bogs or the shallow portion of a pond garden. We like to grow them in pots, where they are very content and have the added benefit of being mobile.
When You Receive Your Bulbs
We ship dormant bulb-like corms in the spring and fall. Spring-received plants may be planted immediately or stored for up to a week in the refrigerator. They will be emerging from dormancy, so you don't want to hold them for too long. We've had good luck storing Fall-received corms in the crisper section of the refrigerator until Spring. Follow our over-wintering instructions below.
Grass pinks require full sun for most of the day. A few hours of shade, especially during the hottest hours, is acceptable.
We use a 1:1 mix of medium perlite and sphagnum peat moss. Rinse the perlite prior to use and be sure to use gloves and a face mask when handling both of these components. We like these components because they are relatively uniform, regardless of where you live. Others suggest half sand, half sphagnum peat moss, with a little charcoal chips added (optional). Pure sphagnum peat moss will also work. These mixes will work as a potting mix or in artificial beds.
Grass pinks require consistent and even moisture. They are not aquatic plants and do should not be submerged. For container culture, you have two options. First, you can grow them in tall pots (6" or more, with drainage holes) and place the pots in a shallow tray of water. Alternatively, you can use pots without drainage holes and drill holes a few inches from the bottom. This will create a reservoir and moisture will be wicked-up through the soil substrate. We use only rain or distilled water for our pinks.
Plant corms so that the tip of the growth bud is one inch below the soil surface.
For container-grown plants, a general, all-purpose fertilizer can be applied every three to four weeks at up to 25R% the recommended strength. Flush the media thoroughly with rain or distilled water prior to application.
Moisture requirements: keep wet at all times, even after they have gone dormant. In sealed container or artificial bog, keep water table level six to eight inches below surface of soil media. Use of rain or distilled water preferred.
Fertilizing: general all-purpose fertilizer at 10-25% strength recommended for pot plants. Apply every three or four weeks up to mid-July. Flush media with water before next application.
Grass pinks are generally hardy to Zone 4. We mulch our beds with pine needles or straw to conserve moisture and prevent heaving and thawing. To aid with Spring cleanup, we cover the beds with thin landscape fabric (ie. weed block). Container-grown plants can be kept in a detached garage, shed, or other such structure. The corms can also be stored in the crisper section of the refrigerator for 4-5 months. Here's how we do this:
After plants enter dormancy, gently remove soil to release the corm(s). The past-season's corm will be somewhat shriveled, but attached to it will be next-year's corm, which will be firm and glossy. If you're lucky, perhaps you'll have more than one new corm. Detach the old and discard. Cut-away the roots from the new corms. Dust with garden sulphur and then place in a zip-style freezer bag with very slightly moist sphagnum moss, peat moss, or sawdust. Place bag in crisper or other part of refrigerator that will maintain temps around 45 degrees. Check the bags each month to make sure there's no spoilage. Discard any corms that are rotted.