Mail-order companies offer an enormous selection compared to that of garden centers or nurseries. Seeds and bulbs, in particular, are easy to purchase through catalogs or web sites because they are lightweight and sustain little or no damage in transit.
To keep freight costs down, most live plants are shipped as “bare-root” stock, with soil washed away and roots cushioned in a wad of damp sphagnum moss, shredded newspaper, or sawdust. Shipping plants this way can take its toll, so inspect plants carefully when they arrive. Superficial damage such as a broken root or snapped-off branch tip can be remedied by pruning away the broken piece. However, if the root mass shows signs of rot or fungus growth, or if the main stern is broken in two, request a replacement or refund.
Bare-root stock should be put into the ground as soon as possible after it arrives. Before planting, immerse the roots in a bucket of water for an hour so that they can take a long drink. When planting, make a mound of soil at the bottom of the hole and splay the roots around it in an octopus formation.
In the world of mail-order merchandising, there are general practitioners and specialists. If you want to make a collection of a particular plant genus—such as daylilies, iris, or daffodils—seek out companies that specialize in that plant group. Many of these firms offer special varieties available nowhere else and have developed custom shipping containers to ensure safe passage of their products. Also, their plant stock will usually be superior to that in a general catalog.
Some catalogs may offer a choice of sizes. For example, a rose catalog may advertise #1 grade, #1-½ grade, and #2 grade plants at progressively lower prices. The lowest-priced plants are usually the runts or culls and should be avoided.
A final caution: The mail-order world is full of get-rich-quick schemes. If it sounds too good to be true, it probably is. It is wise to buy from well-known companies whose catalogs avoid puffery. For a full list of seed and plant sources, see Barbara Barton’s excellent book, Gardening by Mail.