Urban Gardening

August Q and A

Virginia bluebells have true blue flowers.

Thanks to everyone who submitted questions, comments, and ideas. Your feedback is important to shaping and developing this newsletter. I may not be able to answer each question directly, but I will keep them in mind when choosing topics for future newsletters. Thanks for accompanying me along our urban gardening journey.

Question: What easy-care city plants have truly blue flowers? Most of the things I hope will be blue come up purple.

Answer: I love blue too, and you're right, most of the flowers described as blue are shades of purple. So either the advertisers are deceptive, colorblind, or both! But whether you garden on an exposed balcony or in a shady backyard, there are flowers to bring you the blues. Try some of these true-blue favorites:


  • Big leaf hydrangea (Hydrangea macrophylla). There are several varieties with blue flowers, including 'Endless Summer', which blooms on both new and year-old wood and is thus the best choice for northern gardeners. Add acid fertilizer for the bluest flowers.
  • Bluebeard (Caryopteris) is covered in clusters of flowers in late summer.


  • Squill (Scilla) is a small bulb that creates pools of blue in early spring.
  • Spanish hyacinth (Brimeura) is another small bulb with tiny blue flowers in early summer.
  • Forget-me-nots (Myosotis) are common spring bloomers for gardens and containers in shady spots.
  • Lungworts (Pulmonaria) are available in many colors. Plantings designed with combinations of the blue and white cultivars are particularly striking.
  • Virginia bluebells (Mertensia) light up the eastern woodlands in April with pendulous bells of sky-blue flowers.
  • Bachelor's buttons (Centaurea) sport unique flowers with blue petals.
  • Bellflower (Campanula) varieties are usually purplish, but a few are quite blue.
  • Gentian (Gentiana) species and cultivars are famous for exquisite blue flowers. There are alpine, meadow, and woodland varieties of this favorite.
  • Delphiniums are available in a wide range of colors including light to royal blue, but they can be a challenging urban plant.


  • Borage (Borago) is an herb with edible blue flowers that taste like cucumbers.
  • Some cultivars of the trailing plant Nemophila have bluish blooms.
  • Morning glory vines (Ipomoea) have blue cultivars. They are reliable bloomers that quickly cover fences, arbors, and balcony railings.
  • The most commonly planted blue flower is probably trailing lobelia. This creeping annual can produce mats of blue in the garden and mounds of blue in hanging baskets.

Many sedums tolerate infrequent watering.

Question: We have a condo in Destin, Florida, and I'm aching to get plants on the deck. However, we are only there sporadically, so there's no way to provide regular watering. We can count on someone being there each month for at least a few days, but not full time. Any ideas?

Answer: There are not many plants that can survive in containers on a deck with only monthly visits, even in humid Florida. You have to look for plants that survive with scattered rainfall and neglect.

Succulents fit the bill. Varieties of sedum, agave, yucca, hens and chicks, ice plants, and some cycads would be suitable to your subtropical conditions. They don't require much water and are used to maximum exposure. Many bulbous plants could also thrive there because their seasonal growth patterns allow them to grow and bloom when times are good. When conditions are less hospitable, they go dormant and wait. Rain lilies (Zephranthes spp.), magic lilies (Lycoris squamigera), and Aztec lilies (Sprekelia spp.) are tough enough to handle those conditions.

From August 2007 E-newsletter

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