Bees and flowering plants have a long-lasting partnership. The nectar and pollen found in flowers provide essential food for bees.
When bees come searching for food, flowers get pollinated, and seeds are formed. So, the simple act of a bee visiting a flower means that two very different organisms can go on living.
This is why, in order to conserve bees, we need flowers. A garden planted with a variety of flowers that bloom throughout the season has the potential to support numerous species of bees and other pollinators.
But some flowers are better at feeding bees than others. Choosing the right flowers for our pollinator gardens will ensure that bees will be buzzing, happily fed all season long.
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Look for blues and purples
Flowers that are particularly attractive to bees bloom during the day, are shades of blue or purple, and have abundant nectar or pollen.
Other bee-friendly attributes include small flowers arranged in spikes, globes or platforms, and flowers that are bowl-shaped (i.e. poppies, mallows and wild roses) or irregular (i.e. salvias, penstemons and sweet peas).
Bees are known to visit flowers of all sorts of colors; however, flowers that are shades of blue and purple with markings in ultraviolet and polarized light tend to be specifically adapted for pollination by bees. Few flowers are truly blue.
Plants do not produce blue pigments, so the color blue is achieved by varying levels of other pigments or through structural or chemical modifications.
Ceanothus and Caryopteris are two genera of flowering shrubs that include species and cultivars with blue flowers, several of which are suitable for the Treasure Valley.
Commonly known as California lilac, Ceanothus x delilianus ‘Gloire de Versailles’ produces large clusters of powder blue flowers throughout the summer.
Cultivars of Caryopteris x clandonensis, or bluebeard, also flower in the summer. Loaded with blue-purple flowers, they are veritable bee magnets.
Start with perennials
Options for bee-friendly perennial plants are so numerous that no gardener should have trouble finding a few that work for them. Perennials provide a reliable choice for both gardener and bee, putting on a show and producing bee food year after year.
The mint family is a good place to start. From salvias to catmints to hyssops, beautiful, summer-long, blue-purple flowers abound. Try woodland sage, Salvia nemorosa ‘Caradonna’, for its compact, upright form and its spikes of blue-violet flowers and purple stems.
Or consider giant purple sage, Salvia pachyphylla, for its grey-green foliage, its tolerance of dry soils and its big clusters of purple flowers that draw in bumble bees. Walker’s Low catmint (Nepeta racemosa) forms a short, spreading clump that is loaded with bee-friendly flowers throughout the summer and requires very little maintenance. Azure blue sage (Salvia azurea) flowers in late summer and produces whorls of blue flowers atop tall stems.
Penstemons are an excellent native option. For blue-purple flowers in spring and early summer, try Rocky Mountain penstemon (Penstemon strictus), Royal penstemon (Penstemon speciosus), Venus penstemon (Penstemon venustus) or Payette penstemon (Penstemon payettensis).
For flowers throughout the summer, choose from the many cultivars of Penstemon x mexicali, such as Shadow Mountain and Pike’s Peak Purple.
There are numerous other options for blue flowers in the summer, including the tall, regal spikes of Veronica ‘Sunny Border Blue,’ and the unique, rounded flower heads of sea holly (Eryngium maritimum) and globe thistle (Echinops spp.).
For fall flowering perennials, choose from the many varieties of asters, like Frikart’s aster (Aster x frikartii ‘Monch’) or Aster oblongifolius ‘October Skies.’
Add in some annuals
Annuals can also offer a great single-season selection of blue and purple flowers. Borage and phacelia are in the same plant family and are frequently grown to attract bees to vegetable gardens.
Phacelia tanacetifolia is so enticing to bees that one of its many common names is bee’s friend. Monarda citriodora, commonly known as lemon horsemint, is an annual bee balm that produces attractive spikes of pale purple to pink flowers that call in hummingbirds and butterflies along with bees.
Blue anise sage (Salvia guaranitica ‘Black and Blue’) is grown as an annual in the Treasure Valley and produces dark blue flowers cupped in black sepals — a stunning plant especially when grown en masse.
Finally, the native annual Rocky Mountain beeplant (Cleome serrulata) produces fascinating flower heads that are irresistible to a wide range of pollinators.
This is only a smattering of plants that will feed the bees. Visit the Idaho Botanical Garden to see these and other bee-friendly plants in action, and plan on adding some new favorites to your garden this year. The Idaho Botanical Garden is at 2355 Old Penitentiary Road in Boise. Learn more at idahobotanicalgarden.org.
Daniel Murphy is a horticulturist at the Idaho Botanical Garden.