Gardening - Perennially Yours August 2008 Q & A

Answer: Welcome to the challenge of getting three seasons of bloom from shady perennial gardens. Most shade perennials bloom in the spring or early summer before trees leaf out heavily. By late summer, most of the color in shade gardens is provided by annuals or showy foliage. But there are a few plants that will provide a floral encore. Toad lily (Tricyrtus) has darling, orchid-like flowers that are usually white or pink with purple spots. Tricyrtus ‘Gilt Edge’ goes one beauty step farther with its cool gold-rimmed leaves. Yellow waxbells (Kirengeshoma) displays dangling, soft yellow flowers on a three foot tall, shrub-like plant with maple-shaped leaves. The monkshood (Aconitum) family includes a number of cultivars, some bloom in the summer and others wait until cooler weather to do their thing. Monkshood ‘Spark’s’ (violet-blue) and carmichaelii ‘Arendsii (deep blue) are two late bloomers that soar to 4’ to 5’. Eupatorium r. ‘Chocolate’ is typically sold as a sun to part sun perennial but I have it in my filtered shade bed and it does great. It has chocolate foliage with dainty white flowers and reaches 3’to 4’. Lily turf (Liriope) has pretty purple spikes and grassy foliage. It only gets 12” – 18” tall and is hardy to zone 5. Liriope ‘Silver Dragon’ has stunning silver and green leaves that glow in the shade. To supplement flower color in the fall, I plant some shade-loving annuals that do not require deadheading, such as impatiens, browallia, and tuberous begonias.

Question: My delphiniums only seem to live a year or two and then they die. Am I doing something wrong?

Answer: Welcome to the world of short-lived perennials. I know that sounds like an oxymoron. Despite the fact that perennials are supposed to live for many years, there are some that call it quits early. Delphiniums are one. Others are blue flax, verbascum, broad-leafed coreopsis (tickseed), pincushions flowers, basket-of-gold (aurinia), lupine, and many shasta daisies. Most delphiniums live for two to three years in our area. If you get more than that, give yourself a pat on the back. Delphiniums demand good drainage, especially in the winter. Wet feet spell death for them. They do best in full to part sun and benefit from a May application of time-released fertilizer. I use Plant-Tone (organic) or Osmocote 14-14-14. Simply scratch one of these into the soil around their base and water in well. This will provide these heavy feeders with an ongoing supply of nutrients for three to four months. If you get sick of replacing these finicky perennials, you can substitute some tougher look-alikes. Agreed, the following don’t exactly resemble delphiniums, but use your imagination. Nice choices include monkshood (please note that all parts of this plant are poisonous); acanthus hungaricus (Hungarian bear’s-breech, zone 5); alkanet (anchusa ‘Loddon Royalist’, a biennial); salvia pitcheri (zone 5); and false blue indigo (baptesia).