Bee Friendly Gardens. Not All Flowers Are Created Equal:
Barbara Thompson, Pualani Bee Farm
June 24, 2020
As a long-time gardener and new beekeeper, I have become interested in learning about which kinds of plants to use in creating a bee-friendly garden or landscape. With plans to transform existing landscaped parts of our property into gardens that attract bees, I hope to provide them with greater nutritional diversity to help protect them from parasites, diseases, and temporary food shortages. Having searched the internet for recommendations, I have come to realize that bee-friendly landscaping can be as simple as placing a targeted selection of nutritious plants in pots on a lanai, filling a planter with an assortment of herbs, hanging baskets with a colorful splash of flowering ornamentals, or allowing a sunny part of the property return to a wildflower meadow. With 3.5 acres of mostly “out of control” coastal forests comprised of lauhala, palms, and an endless number of invasive plant species, I want to incorporate designated bee gardens into our little “jungle.” As beekeepers, this will help us to support the wellbeing of local bee populations while as lovers of the land, we can attempt to restore our property to less invasive ecosystem.
Bee Garden Development and Local Plant Nurseries
In the world of bees and bee nutrition, not all flowers are created equal. Certain plant species yield higher value nectar (carbohydrates) and pollen (protein), which bees need to augment the quantitative and qualitative diversity of their food resources. Diversified gardens featuring a large variety of bee-friendly blossoming plants can help Hawaii’s honeybees consume a more nutritious diet of nectar and pollen on a year-round basis.
First and foremost, gardeners should eliminate the use of herbicides and pesticides, or, at the very least, reduce chemical use or select the least toxic alternatives. If non-organic herbicides and pesticides cannot be avoided, read labels carefully, and apply in the evening when most foraging bees are inactive. Better yet, consider using natural remedies. Knowledgeable plant specialist(s) at local nurseries can suggest organic remedies for killing weeds and controlling pests. They can also provide important advice on selecting plants that are naturally pest-resistant or less susceptible to infestations.
Each island in Hawaii has a unique biodiversity. Selecting plants for bee-friendly gardens should take into account the local environment, such as island-specific conditions, elevation, and microclimates (e.g. windward or leeward side of the island, dry, mesic, or wet, coastal, mountainous, high altitude, etc.). The experienced staff at local nurseries can provide helpful advice on which plants flourish under the specific conditions of your garden setting and supply plants that have been raised in the same or similar circumstances.
To provide optimal and diverse resources for bee diets, selecting the right plant species is key to the planning of a bee garden. Nutritionally balanced sources of nectar and pollen are especially critical during periods of bee reproduction and development. Unfortunately, most literature on the nutritional value of beneficial plants in honeybee diets focuses on mainland species from different climatic conditions. Honeybees love berries, wildflowers, flowering vegetables, fruits, flowering herbs, and flowering trees. Some of the plants recommended for mainland bee gardens might be invasive in Hawaii. Therefore, consulting with local nurseries can help in identifying related native, naturalized, or non-invasive alternatives that will not compete with endemic plants.
Given the sensitivity of Hawaii’s ecosystem, it is vital also to be educated on the potential impact that each plant might have on the local environment. With the increasing importance of beekeeping in Hawaii, studies on local plant resources for bees are now available online (see links to suggested readings at the end of this blog) and are an important aid in planning and selecting plants for a bee garden.
Edibles, Herbs, and Hive Health
It is widely known that bee pollination is critical to the yield, weight, and quality of many important fruits, vegetables, and edible crops. In Hawaii, bee pollination is beneficial to several locally grown food resources. These include, for example, macadamia nuts, coffee, lilikoi, guava, rambutan, lychee, strawberries, citrus fruits, cucurbits (members of the gourd family, such as cucumber, squash, pumpkin, zucchini, and melons), eggplants, beans, onions, and peppers.
Other crops, such as allspice, avocado, cashew, okra, pimento, coconut, mango, safflower, and sunflower, can prosper in Hawaii’s mild climate and benefit from bee pollination. Moreover, bee pollination helps certain crops to produce seed, such as asparagus, carrots, and broccoli, thus ensuring subsequent harvests. Although beans, cabbage, cauliflowers, eggplant, kale, lettuce, sweet potato, and peppers do not require bee pollination, their flowers serve as a viable food source for these pollinators. Most edible plants that benefit human and bee alike are easily integrated into existing gardens, farms, or landscapes.
Bee pollination improves also the growth of various herbs, which play a vital role in human diets and culinary practices. Evidence suggests that many of the common garden variety of herbs are a great source of food for honeybees. These herbs have antimicrobial and antifungal properties that help prevent pests and diseases within hives. Thus, planting a diversified herb garden enables not only a rich human culinary experience but also contributes to over health and strength of bees and their colonies.
Though not native to Hawaii, many herbs from the Lamiaceae family, such as mint, sage, rosemary, oregano, and thyme, attract honeybees. These herbs are especially great forage sources as they continuously reproduce long spikes, or inflorescences, of small flowers for several days. The bees learn to return to these herbal patches in search of their tiny nutritious blossoms.
In Hawaii, however, some herbs can be particularly invasive, such as mint. So, these are best planted in large containers and interspersed between other herbs planted in the ground. In areas with shallow soil, a container garden of thyme, rosemary, oregano, marjoram, sage, parsley, fennel, dill, and basil can be an especially rewarding and healthy nutritional supplement for bees and humans alike.
For bees, thyme blossoms are an excellent source of nectar. Also, thymol, an active constituent in thyme, can effectively treat varroa mites (one of the great parasitic banes of beekeeping!). Bee balm is another bee favorite herb, as the name suggests. Like thyme, bee balm contains thymol and is naturally antimicrobial. Chives is an herb that repels most insects but attracts bees! In this capacity, chives help reduce the competition that honeybees face with other insect pollinators. Lemon balm is a huge source of nectar and pollen for the bees and therefore helps them to increase their honey production. Lavender, which is rich in beneficial nectar, is a wonderful addition to a garden, as well as hawthorn (also medicine for humans), borage, and calendula. Edible flowers such as nasturtiums, pansies, violets, impatiens, single zinnias, cosmos, and sunflowers are all delicious and colorful additions to salads in human diets. They also help support diversified bee nutrition. Since many of these non-native edible plants are invasive in Hawaii, they are best reserved for container gardening.
Bee Foraging and Floral Diversity
With its tropical climate and year-round growing season, Hawaii is blessed with constant nectar flows from native and exotic flowering trees that are abundantly present in our local landscapes. These flowering trees are a critical food resource for pollinators of all kinds, including honeybees. The nutrient-rich pollen and nectar of flowering trees provide bees with important resources that contribute to year-round production of honey, bee pollen, beeswax, and propolis.
In my community of Wa’a Wa’a, for example, we are surrounded by Jurassic-looking rainforests that cover ancient lava flows aged between 1500-11,000 years old. These rainforests are dense with a huge diversity of flowering and non-flowering plant species. They grow in complex, intertwined, and canopied layers. A diverse range of blooms appear and disappear throughout the year, thus benefitting the pollinators in this coastal region.
We also live within a few miles of newer landscapes from lava flows as recent as 2 to about 350 years ago. These landscapes are initially barren but eventually begin to sprout with occasional ferns and new growth ’ohi’a lehua trees. This latter Hawaiian native flowering tree contributes to one of the most prized crystalized honey varietals in the islands. Over time, mostly non-native trees, such as albizia, melocia, and ironwood, among others, have taken over the surface of now aging lava flows. Honeybees forage these exotic trees as important food sources and for the production of propolis. However, these tree species are among the Big Island’s most invasive plants!
Consequently, we have slowly been removing the more obnoxious invasive trees from our property, knowing that their abundance in our community and the nearby Nanawale forest will continue to nourish our local bee population. In their place, we are planting bee-friendly and Hawaii-friendly alternatives, such as ’ohi’a lehua, kukui, and hau trees, among other native, naturalized, and non-invasive species. With an eye toward floral resource diversity, we hope to provide our bees with healthier foraging and dietary options from which they can self-select, thus sustaining healthier hive populations and reduced risk of diseases, pests, and stress (more on this last point in another blog!).
Our property is located on an ancient lava flow. Modern era land disturbance, however, has enabled an excessive number of invasive tree and shrub species to flourish here. For example, honeybees love the minuscule but abundant flowers of the lantana, wedelia, and false heather (or “Hawaiian heather”). Though lovely to see these colorful accents popping up in the neglected parts of our property, these non-native ornamentals are highly invasive! Except for a few “controlled” clumps of heather (which our bees love!!), we are continuously removing these scattered invasive plants, replacing them with native Hawaiian shrubs and ground covers. Some of the many native species that attract pollinators and are good sources for bee foraging, for example, include naupaka, ilima, and opelu; native “ice plants,'' such as akulikuli; and indigenous ground covers, such as native yellow purslane, akia, and eluehe (see online resources listed below on native Hawaiian bee-friendly plants).
Bee Garden Tips
With Hawaii’s year-long planting season, a bee-friendly garden takes into consideration the various blooming cycles and seasonal variations of temperature, weather, and wind. This ensures the bees have constant and diverse source of food and foraging in an ever-blooming environment. Although plantings with long or successive blooming cycles are the best for bees, maintaining plant diversity will help to offer them greater nutritional variety.
Consider replacing part (or all) of your lawn with different flowering plants, rather than the single species of grass, including a selection of flowering trees, bushes, ground covers, and vines that blossom at different times of the year. Planting vegetables and herbs in stages throughout the year will allow for constantly changing periods of blossoming. Select plant species with single versus double-headed flower tops. Although double-headed flowers are pleasing to human eyes, they produce much less nectar and make it harder for bees to collect the pollen.
Highly hybridized plants, with their complex structural forms of flowers, should be avoided as they produce very little pollen and nectar for bees. Despite the ubiquitous presence of many colorful, ornamental plants in Hawaii, such as bromeliads, heliconias, birds of paradise, and gingers, these provide little food for insect pollinators. Therefore, interspersing bee-friendlier plants between existing exotics will go a long way in augmenting the health of honeybees without forsaking the tropical character of Hawaii’s gardens.
Many bee-friendly and bee favorite plants have tiny or inconspicuous flowers. Planting the same species of such plants in larger, more noticeable clumps or clusters will attract bees more effectively than single stand-alone plantings. Locating shorter plant species between taller ones increases the bees’ efficiency and saves them energy expended on foraging. Such layered displays provide more economical use of garden space—hence less labor for the gardener as well!
Plant groupings can be arranged by the colors of their blossoms. Honeybees seem to prefer blue, purple, violet, white, and yellow blooms, which can be clustered together. Plants can also be grouped according to the season in which they blossom and the durations of their blooms. A revolving display of flowering plants appeals not only to human aesthetics throughout the year but also to the nutritional needs of bees.
Bees need fresh, clean water—preferably rainwater. Natural or human-made water features are an important element of bee-friendly gardens and might include running water or a pond with shallow or sloping sides or floating-leaved plants to allow them to easily drink without drowning. Transforming a shallow container, such as a dish, tray-tiered planter, or birdbath, into a honeybee watering hole is a quick and easy method of creating a water feature. By filling the container with cinder rocks, pebbles, marbles, sea glass, or twigs that stick out of the water's surface, the bees can land and drink without drowning.
Living in the rainforest where we have precipitation most nights or mornings, it is easy to ensure that our bees have a fresh spattering of water on our plants throughout the year. However, the occasional drought can leave shallow water containers dry in no time at all. To ensure that the bees can return to the same spot every day for their drinking needs (and reducing their often fatal visits to our swimming pool!), I converted a glazed ceramic flower container into a bee drinking hole by using a floating miniature solar-powered water fountain (about $7) to keep the water fresh and oxygenated. A round piece of screen, cut to the same diameter as the container and with a small hole in the middle for the fountainhead, floats atop the water. This allows the bees to land directly on the water’s surface. For gardens in drier microclimates, filling a large bucket or tub with water and then covering its surface with floating wine corks achieves the same effect of a landing surface for the bees.
All the ideas presented here can be incorporated into existing gardens and landscapes in phases and over time so that humans and honeybees alike are equally served by the fruits of the gardener’s labor. Starting a new garden—be it smaller or larger—designed specifically for these little pollinators, can be a real joy, especially in the sudden presence of bees in the quiet corner of one’s property where there once were none. In either case, the bee-friendly gardener inevitably will learn about the mysteries and virtues of particular plants and garden design elements through the prism of the bee’s eyes while also taking part in strengthening the health, wellbeing, and resilience of Hawaii’s honeybees.
Sources Consulted and Suggested Readings: Hawaii-specific
Sources Consulted and Suggested Readings: General
(NOTE: Not all plants listed in the following readings are appropriate for Hawaiian gardens due to the risk of invasiveness)