Once you have decided what kind of plants you want to grow and where they will be planted, you are ready to purchase plants! You may prefer to raise most of your plants from seed yourself, but if you have seen some penstemons and are eager to grow them, you will want to purchase a few plants to enjoy while waiting the year or two that seeds take to become plants full of bloom. (Don't be reluctant to buy a plant that you can't immediately think of a location for; you can enjoy and learn from it even if you don't have a perfect location!) If you are looking for common ones, there will usually be many hybrid penstemons and a few species in most local independent nurseries. Look for nurseries that specialize in wildflowers for more species. (click here to see list of nurseries) You may even find some, such as 'Husker Red', P.barbatus hybrids and the 'Mexicali' hybrids in the giant hardware, discount and food store nurseries. All plants should be carefully examined to be sure they are insect and disease-free before purchase. Some growers recommend quarantining plants from unknown nurseries, plant sales or acquaintances for a few weeks. Plants should not have roots spiraling around the inner wall of the pot or extending through the drainage holes. Look for deep pots. Unless you live in one of the unusual and special areas where anything will grow, choose young, small plants as early in the spring as available. You might call your local nurseryman, visit the Ineternet, or contact the many mail order suppliers listed on this website in the fall or winter to ask if you can obtain particular species that you want while they are small. Too often local nurseries cater to those who will only buy plants when they see them in bloom. This is fine for many plants-- annuals particularly, but most perennials need a while to get well established in the garden before it is time for them to bloom, especially where late spring and summers are hot and dry. Some nurseries do "up-pot" their plants into soil that is close enough to garden soil that they can be transplanted directly into good garden soil during the late spring and summer without disturbing the roots, but a plant that has had a longer time to become established in the garden will generally perform better. In areas where fall is long and winter comes gradually, young plants can be set out in late summer or early fall and will be very well established by their bloom time. Consult your American Penstemon Society website or a reputable nursery or other gardeners in your area about fall planting. Although the many penstemon species grow wild around the country along roadsides, it is not a good idea to dig them from the wild. Federal and state laws prohibit collection in most parts of the country and full grown plants do not survive digging.

Selecting, Growing and Caring for Penstemons
From Chapter 41

Lindgren, Dale and Wilde, Ellen. 2003. Growing Penstemons: Species, Cultivars and Hybrids: American Penstemon Society. 519 West Lancaster Avenue, Haverford, PA 19041-1413 : pp. 105-110