Gardening for Bees - or not!

Whitney Cranshaw
Department of Bioagricultural Sciences and Pest Management
Colorado State University

HONEY BEE
Scientific Classification: Apis mellifera (Family: Apidae)
Social Structure: Social insects with distinct castes: queen (fertile female), workers (non-
fertile female), drones (males)
Nest Construction: Wax produced from glands of the body and drawn into hexagonal cells.
Almost all hives currently are maintained by beekeepers; feral (wild) colonies originating from
swarms may occur in aboveground cavities such as hollow trees or in wall voids of buildings.
Life Cycle: Colonies are perennial. Queens may live for several years, workers and drones for
months. Workers and drones are produced continuously from mid-winter through late summer.
Queens are produced periodically during this period, particularly in response to overcrowding or
decline of the existing queen. New colonies are formed by colonies splitting (swarming), with a
single queen leaving with a large percentage of the workers.
Feeding Habits: Nectar and pollen are the primary foods. Other sweet materials may
sometimes be taken such as honeydew and sugary drinks.
Sting: Stinger of the workers is barbed and is pulled out in the act of stinging. Queens have a
barbless stinger. As the stinger is a modified ovipositor possessed only by females, drones do
not sting. Sting is quite painful.

The issue of having honey bees as a garden visitor can be a bit more complex than with some
other insects found in gardens. These insects are well recognized for their highly beneficial
activities as pollinators and as producers of highly valued products such as honey and bees wax.
In this regard one may wish to provide plantings that are utilized by honey bees.

On the other hand they sting. And, although while foraging they are not aggressive and will not
sting unless confined (perhaps accidentally), they do often produce anxiety. Large numbers of
honey bees foraging as some sites may not be desired.

The following is a list of plants that are highly visited by bees - the “Bee List”. It is followed by
plants that are not visited by bees. These constitute the extremes among over 200 species of
plants that were evaluated between 2006-2008.

Several plants are heavily visited by honey bees with plants in the families Lamiaceae,
Asteraceae and Cleomaceae particularly well represented:

Table 1. The “Bee List” (Plants Highly Favored by Honey Bees)

Agastache foeniculum Allium tangitucum
Aster novae-angliae Berkheya purpurea
Berlandiera lyrata Bulbine frutescens
Calamintha nepeta ssp. glandulosa Caryopteris ‘Blue Mist Spirea’
Chamaebatiaria millefolium Chrysanthemum serotinum ‘Herbstern’
Cleome Cotoneaster
Echinops exalta Eremurus stenophyllus
Ericameria nauseosa Eriogonum jamesii
Eryngium giganteum “Miss Willmott’s Ghost” Euphorbia “Diamond Frost”
Gaillardia aristata Geranium ‘Jolly Bee’
Geranium himalayense Helianthus ‘Lemon Queen’
Heliotropium Inula royleana
Kniphofia typhoides Malva alcea
Nepeta cataria Nepeta x fauseniiOcimum
Origanum Origanum “Hopley’s Purple”
Penstemon eatonii Salvia nemorosa
Satureja montana Scabiosa
Sedum spectabile Senecio
Silphium laciniatum Solidago
Spirea x bumalda Teucrium chamaedrys
Teucrium orientale Thymus kotschyanus
Tilia (linden, basswood) Veronica spicata ‘Sunny Border Blue’
Veronica longifolia “Lavender Charm”

Several plants are not visited by honey bees. Some plants are not normally pollinated by bees
and do not suitably provide nectar or pollen. Other horticulturally modified plants may become
non-attractive, such as cultivars with “doubled” blossoms.

Table 2. Plants not Visited by Honey Bees

Acanthus hungaricus Achillea filipendula “Coronation Gold”
Achillea millefolium “Moonshine’ Achillea ptarmica
Achillea taygetea Alcea rugosa
Alyssum Allium moly
Amaranthus caudatus Ameria meritima ‘Victor Reiter’
Anemone coronaria Anemone sylvestris
Angelonia Anthemis tinctoria
Aquilegia caerulea Aquilegia flavescens
Arabis Argyranthemum
Artemesia ‘Bwis Castle’ Aster sericeus
Aster dumosus Aster x Finalist
Begonia tuberhybrida Brachycone
Callistephus chinensis Camassia quamash
Campanula carpatica Catharanthus roseus
Celosia (most) Centranthus ruber
Cerastrium tomentosum ‘Silver Cape’ Chrysanthemum (most)
Clematis Cornus kousa
Crossandra Cosmos (doubles)
Dahlia (doubled) Delosperma dyeri
Delosperma floribundum Delosperma rugigenum
Delphinium Dianthus (most)
Diascia integerrima Eustoma
Galium verum Ganzia krebsiana
Geranium (ivy) Geranium richardsonii
Geranium sanguineum Gomphrena globosa
Goodenia Heuchera x bressingham
Helichrysum basalticum Helleborus orientalis
Hosta Hyacinthoides hispanica
Hypericum frondosum Hypericum perforatum
Ismelia carinata Lathyrus latifolius
Laurentia Leucanthemum
Manicaria chamomilia Mercardonia sp.
Miribilis multiflora Nemesia fruticans
Nicotiana Nierembergia
Nymphaea ‘William McClane’ Oenothera missouriensis
Osteospermum barberiae compactivum Penstemon pinifolius
Penstemon rostriflores Penstemon ‘Phoenix Violet, Red’
Petunia Philadelphus cornonarius ‘Silver Showers’
Phlox paniculata Phlox subulata
Pinellia spp. Platycodon
Polygonum Portulaca (most)
Pycnanthemum Rheum arstrale
Rudbeckia triloba Rudbeckia “Denver Daisy”
Ruta graveolens Sanvitalia
Scrophularia macranth Stachys officinalis
Syringa villosa x reflexa Teucrium lucidum
Verbena (all) Veronica austriaca ssp. teucrium
Veronica pectinata Veronicastrum virginicum
Vinca (all) Viola (all)

BUMBLE BEES
Scientific Classification: Bombus species (Family: Apidae/Subfamily: Bombinae)
Social Structure: Social insects with castes including queens (fertile female), workers (non-
fertile female), drones (males). There is wide range in size of workers, sometimes described as
being minor or major workers.
Nest Construction: Wax produced from abdominal glands drawn into jug-like containers.
Nests are most often constructed below ground in abandoned rodent nests. Other sites of nesting
might be stuffed furniture or walls with appropriate insulating debris of some sort.
Life Cycle: Colonies are annual. Fertilized queens are the only overwintering stage. Nest
construction begins in spring. Since all rearing is done by the queen at this time the first bumble
bees are almost all minor workers, quite small in size. After they emerge, the workers assist with
colony functions and colonies increase rapidly. By late summer several hundred workers may be
present and some fertile queens and drones are produced. These new queens mate and disperse,
wintering in protected locations away from the nest. Drones and workers die at the end of the
season and the colony dies out.
Feeding Habits: Nectar and pollen.
Sting: Queens and workers can sting, but the stinger is not barbed. Sting is quite painful.
Honey bees and bumble bees may both visit many of the same flowers. However, bumble bees
can access the nectar/pollen from some plants that honey bees do not. Usually these are
somewhat deeper flowers or that have their pollen resources more hidden. For example, bumble
bees will visit many night shade family plants (Solanaceae) that are avoided by honey bees since
bumble bees “buzz pollinate” and can shake the pollen from blossom. Some of the plants often
visited by bumble bees include the following:

Plants Noted to be Most Heavily Visited by Bumble Bees

Agastache rupestris Anemone nemororosa
Cuphea Echinacea purpurea
Echinops Hypericum frondosum
Nepeta Penstemon x. mexicali
Perovskia atriplicifolia Sesili gummiferum
Solidago Symphylum officinale
Veronicastrum virginicum

SOLITARY BEES

LEAFCUTTER BEES
Scientific Classification: Family Megachilidae. Most common are Megachile species.
Another group are the mason bees (Osmia spp.)
Social Structure: Solitary insects with the female doing all nest construction and maintenance.
Fertile females and males are produced.
Nest Construction: Nesting is done alone by the female which emerges in late spring;
overwintering occurs as a larva within the nest cells. Nests usually are excavated out of soft,
rotten wood or the pith of plants. However, they will nest in existing holes of the proper size,
including holes in clay banks or stone walls. Some leafcutter bees are semidomesticated and are
managed by providing them predrilled "bee boards".
After the nesting tunnels are constructed, the female cuts fragments of leaves or flower petals
and uses them to line the tunnels. Individual nest cells are constructed in this manner, somewhat
resembling cigar butts. The cells are filled with pollen and some nectar and sealed. A series of
cells is produced in each tunnel.
The mason bees (Osmia spp.) similarly nest in holes excavated out of wood or pith. However,
their cells are lined with mud and they do not cut leaf fragments.
The wool sower bee (Anthidium manicatum) nests in existing holes/cavities. The nest area is
lined with plant hairs.
Life Cycle: Leafcutter bees have an annual life cycle, with one generation produced per year.
Winter is spent as a full-grown larva in the cell. They pupate in spring and emerge in early
summer.
Feeding Habits: Nectar and pollen.
Sting: Female leafcutter bees can sting, but are very non-aggressive and rarely do. The stinger
is not barbed and is slightly painful.

THE "GROUND NESTING" BEES

Scientific Classification:
Acute-tongued burrowing bees: Family Andrenidae
Digger bees: Family Apidae (Subfamily Anthoporinae)
Sweat bees: Family Halictidae
Note: The following biology for these families is generalized
Social Structure: Solitary insects, but many individuals often nest in close proximity where soil
conditions are favorable. Fertile females and males are produced.
Nest Construction: Nesting is done alone by the female; overwintering stage is a larva within
the nest cell. Nests are constructed by digging in soil. Excavated tunnels branch and are lined
with waxy or shellac-like material and some species re-use tunnels in subsequent generations.
The females provision the nest cells with pollen and nectar.
Life Cycle: Digger bees have an annual life cycle, with one generation produced per year.
Winter is spent as a full grown larva in the cell. They pupate in spring and emerge in early
summer.
Feeding Habits: Nectar and pollen. Some species have highly specialized habits, e.g., certain
digger bees solely visit cucurbits.
Sting: Female bees can sting, but are very non-aggressive and rarely do. The stinger is not
barbed and is slightly painful. Occasional problems with sweat bees do occur, primarily related
to their habit of visiting moisture, including sweat. This may cause them to sting when humans
attempt to deter; the sting is momentarily mildly painful.

The Curious Case of the Wool Carder Bee

The wool carder bee, Anthium manicatum, is a member of the leafcutter bee family
(Megachilidae). Members of this family are solitary bees, each female producing her own nest.
The leafcutter bees either use existing cavities or excavate cavities out of soft materials (pith of
plants, rotted wood, etc.).

The most common leafcutter bees then line the cavity with fragments of leaves they cut from
plants and form into cells. However, the wool carder bee instead lines these cavities with plant
hairs.

Therefore, one is likely to find the wool carder bee where one plants “woolly” leaved plants.
Lamb’s ear (Stachys) is a particularly good plant to encourage the local activity of this insect.

Shelter/Nesting Needs of some Garden Insects

Insects that create nests have special shelter needs that also must be met if they are to be
encouraged in a garden. This need is widespread among many of the bees and wasps. Among
these are the following, along with the type of shelter that can assist their establishment.

Mason bees (Osmia). These are solitary bees in the leafcutter bee family, some of which have
been heavily promoted as good, early season alternatives to honey bees for pollination of fruit
crops. These bees create separate nesting cells through use of mud partitions. Nests that they
use are existing cavities. These can be provided by use of predrilled wood blocks, with a
diameter of about 1/4-3/8 inch. Alternately, bundled soda straws are useful for nesting.
Leafcutter bees (Megachile). These are the most commonly recognized of the leafcutter bee
family as they produce characteristic semicircular leaf cuts when harvesting leaf fragments for
nest construction. These will nest in predrilled wood, similar to the mason bees. They will also
excavate their own cavities out of rotten, soft wood. Large diameter branches or stems of pithy
plants may be used by some species.
Leafcutter bees (Anthidium). These leafcutter bees line existing cavities with plant hairs rather
than leaf fragments.
Ground nesting bees (Andrenid bees, digger bees, sweat bees). Several groups of solitary
bees nest in soil, rather than using aboveground cavities. Slope, soil texture, and surface debris
are all critical in the selection of a nest site by these bees. It is difficult to develop a site that may
be used by these bees; instead conservation of bee nesting sites that have been accepted and used
by the bees is recommended.
Paper wasps (Polistes). These common social wasps can sting. However, they also have a
tremendous appetite for many of the more important garden pest insects, notably caterpillars.
The paper wasps for open-celled paper nests that hang and open downward. Nests are
constructed in areas of shelter, typically some overhang (e.g., eaves) or in small cavities. Rough
metal or wood surfaces are particularly acceptable by these insects.
Pith nesting hunting wasps. There are many common species of solitary hunting wasps in the
family Sphecidae. These are docile (to humans) and specialize in certain insects. Each
constructs their own nest, with some nesting in soil like the ground nesting bees. However,
among the more common in yards/gardens are small wasps of the genus Pemphredon. These
specialize in hunting aphids, which they paraliyze and cache within the pith of plants. Old cane
or other pithy plants provide excellent habitat for nesting. These will also nest in cut rose canes;
their subsequent nesting is confined to the pith area and causes very little, if any, harm to the
plant.
Mud daubers. The black-and-yellow mud dauber (Sceliphron caementarium) can be a fairly
common insect that produces a unique mud nest in the form of tubes. These wasps hunt spiders,
which they paralyze and cache in the mud nest. The presence of a muddy spot is need for
nesting by these insects. Nests are commonly established on the sides of buildings under some
overhang shelter.

Reference: Nuisance Bees and Wasps

Available online at: http://www.ext.colostate.edu/PUBS/INSECT/05525.html

A Note on Bee Mimics

There are several insects that will mimic bees and wasps. This mimicry may involve yellow and
black or orange/black markings, which are generally used as warning colors. This mimicry may
extend further, with some insects buzzing like bees or having a hairy appearance.

Most often insects that mimic bees are some kind of fly. The family Syrphidae, known as
“flower flies” or syrphid flies, are particularly common in yards and gardens. However, certain
beetles, moths and other insects may mimic a bee or wasp.

Known of these mimics can sting and all are harmless. The ability to sting is limited to female
insects of the order Hymenoptera – the bees, wasps, and ants.