The common but beautiful foxglove (Digitalis purpurea) is a biennial best grown from seeds. This is the foxglove most prominently featured in the American Impressionism exhibit. Biennial foxgloves can be started from seed in alternate years so that you will have flowering foxgloves every year.
The best time to sow foxglove seeds is in late summer. They need light to germinate, so sow them by simply scattering the seeds on the top of the soil. Then gently rake the seeds into the soil, but do not bury them. Foxgloves are rather slow to germinate, so you won’t see any seedlings for 20 - 30 days. They can also be started indoors in winter or spring and planted out in summer.
While not on display in our 2016 exhibition, perennial foxgloves are also worth considering for your garden. Perennial foxgloves can often be found in nurseries as potted plants. Digitalis grandiflora is a yellow–flowering species with gracefully arching spires. A variety termed ‘Polkadot Polly’ has pink-apricot-colored flowers. ‘Spice Island’ is a cream-colored perennial.
Foxgloves grow best in dappled shade, with other perennials, or in a woodland garden. They will grow in USDA zones 4 - 8. They need moist but not waterlogged conditions. A layer of mulch around the plants is helpful, as well as compost-amended soil. The compost conditions the soil, helping plants take up nutrients easily.
The American Impressionism exhibit included a new introduction to the plant world that closely resembles foxglove. Digitalis Illumination Series (synonym Digiplexis or Digitalis x valinii Illumination Series) is a hybrid plant introduced in 2006 (but generally available only about ten years later) as an intergeneric cross between Digitalis purpurea and Isoplexis canariensis. (Some of the confusion with the name stems from the fact that Isoplexus has since been placed in the genus Digitalis.) This exciting introduction is known for its long-lasting flowers that share the bright coloring and shape of Isoplexus on the tall stalks of Digitalis. Because it is sterile and doesn't waste energy producing seed, it grows tall and full quite quickly. Sadly, these plants are hardy only to zone 8, so not in the New York City area, but make bold additions to a garden as an annual.
Warnings: Foxgloves are poisonous, so avoid ingesting any part of the plant. They can also become invasive by self-sowing. To help prevent this, cut the flowers stems before they form seeds. ‘Spice Island’ is sterile, so this foxglove does not self-sow. On the positive side, deer and rabbits usually avoid foxgloves.
American Impressionism and Realism by 
Impressionist Garden by 
Impressionists in Their Gardens by 
The American Impressionists in the Garden by 
