Gardening Pollinators (Radell)

Attracting Pollinators

and Other Beneficial Insects

marc radell

master gardener volunteer

montgomery county, pa

agenda

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Overview of

pollination

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Pollinators in Peril

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Gardening for

pollinators

www.marcmradell.com

Overview of Pollination

plant classification

~258,650 species ~860 species

Flowering plants

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angiosperm = enclosed seed

²

angiosperms have flowers and fruit

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flowers = reproductive organs

²

fruit can be fleshy or dry

pollination

² required for sexual reproduction (making seeds)

² pollination = transfer of pollen to stigma

² fertilization = union of male and female germ cells

² one pollen grain per seed

Ovule

asexual reproduction

² involves a single parent plant

² produces genetically identical clones

² some plants can produce seeds

without fertilization (ex: dandelions)

² most asexual reproduction is

vegetative

ª structural modification to roots, stems, or leaves

ª examples: bulblets (lily), stolons (strawberry), suckers (pawpaw), leaves (begonias)

types of pollination

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cross-pollination

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flowers from

different plants

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genetic diversity

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self-pollination

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flowers from same

plant

or

cross-pollination

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abiotic pollination

(wind, water)

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animal pollination

animal pollination

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75% of plant species rely on

animal pollinators (90% of

flowering plants)

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33% of food crops rely on

animal pollinators (mostly

insects)

how pollinators benefit

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nectar: high in sugar and amino acids

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pollen: high in protein

animal pollinators

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insects pollinate about 70%

of flowering species

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mammals (opossums, mice,

squirrels) pollinate up to 20%

of forest subcanopy and

understory

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ruby-throated hummingbirds

are prime pollinators of about

19 native plants in

Pennsylvania

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slugs, snails, earthworms also

other benefits of pollinators

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insects and small

mammals are important

parts of the food chain

²

pollinators can have

other beneficial

functions

Pollinators in Peril

threats to biodiversity

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H

abitat Loss

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I

ntroduced species

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P

ollution

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P

opulation Growth

²

O

verharvesting

the way we were

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Penn’s Woods characterized

by deciduous trees –

seasonal sun and shade,

changing bloom times

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continuous vegetative cover

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multiple layers of vegetation:

tall trees, small trees, shrubs,

herbaceous plants

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multiple sources of shelter,

the way we are

² habitat destruction

ª food

•  quantity

•  quality

ª shelter

•  vegetation

•  duff/leaf litter

•  soil for nesting

ª water

•  wetlands, puddles,

vernal pools, vegetation

² habitat fragmentation

ª smaller blocks of habitat

ª fewer protected travel corridors

ª roads and development as barriers

other perils

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plant monocultures

ª agriculture ª lawns

ª poor landscaping ² poor quality open space ² invasive plants

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climate change

ª affects individual plant species

ª affects individual animal species

ª affects timing between

plants and animals decline in tree species

more other perils

² insecticides

ª agricultural and household

ª most are non-discriminatory

ª non-lethal doses are still harmful

•  colony collapse disorder

•  neonicotinoids

ª PSU study

•  70 pesticides/metabolites

found in pollen

•  average of 6 per pollen sample

ª organic ≠ safe

² herbicides

ª target “weeds”

ª can weaken animal pollinators

ª used to create monocultures

Pollinator Garden Certification

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provide food

²

provide water sources

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provide shelter

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safeguard habitat

http://ento.psu.edu/pollinators/public-outreach/cert

nectar & pollen sources

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use native plants

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4x likelier to attract pollinators

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provide optimal nutrition

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provide flowers from Spring

through Fall

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plant diverse colors, shapes,

heights

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plant in groups or drifts

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avoid fancy hybrids and cultivars

what is a native plant?

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native to geographic

area prior to human

intervention

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PennState/DCNR: native

to Pennsylvania before

European contact

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but you still need to put

the right plant in the

right place

Piedmont

plants.usda.gov

Larval host plants

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caterpillars have to eat,

too!

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many butterfly and

moths larvae eat only

one genus of plants

water sources

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butterfly puddling area

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mud source for mason

bees and wasps

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birdbath or shallow

water source filled with

gravel or sand

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pond, water garden

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stream

shelter

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nesting sites for bees and

wasps

ª

dead wood and stems

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spaces of bare ground

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bee houses

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overwintering sites

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rock pile or wall

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brush pile

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leaf litter

safeguard habitat

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remove invasive plants

ª  multiflora rose

ª  Japanese honeysuckle

ª  Japanese barberry

ª  burning bush

ª  autumn olive

ª  privet 

ª  asiatic bush honeysuckles

ª  oriental bittersweet

ª  butterfly bush

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conserve native plant

populations

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reduce lawn space

safeguard habitat

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reduce pesticide use

ª

Integrated Pest

Management

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use least toxic and least

persistent method

ª

avoid systemic pesticides

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a well-planned and

maintained garden seldom

needs pesticides

121 different

pes8cides have

been found in

honeybee

Gardening for Pollinators

(specific animals)

how plants attract pollinators

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color

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shape

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scent

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markings

insect pollinators

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bees

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flies

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beetles

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moths

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butterflies

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wasps

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ants

Flowers for insects

bees

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bees probably evolved from

flies to feed on nectar and

pollen

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prefer aromatic flowers with

bright yellow or blue petals

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guide lines direct bees to

nectar, may not be visible to

human eye

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social or solitary nesters

carpenter bee

honey bees

²  introduced to U.S. from Europe

²  only commercial source of honey

²  2/3 of hives are circulated for

commercial crop production

²  more important for large-scale farming

than for smaller gardens

²  primary pollinators of almonds, apples,

melons, alfalfa, plums, cherries, avocadoes, pears, cranberries

²  honeybee population has declined 50%

since 1950

²  Colony Collapse Disorder detected in

late 2006, multiple causes including

mites, virus, pesticide exposure, stress tracheal mites

bumble bees

²  most important native pollinator (“buzzing”)

²  17 species in Pennsylvania, classified by tongue length

²  social bees (30 to150 workers per nest)

²  nest in the ground, small cavities, old rodent nest

²  carry pollen to nest in sacs on hind legs

²  may sting to protect nest

solitary bees

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up to 400 species of solitary bees in

Pennsylvania

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live alone or in colonies

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burrow tunnels in soil (70%), wood or small

branches or reuse beetle larva burrows

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carry pollen to nest in mouths

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seldom sting

bee nesting sites

² bumble bees

ª leave areas of undisturbed

open ground

ª small pit (6-8” cube) lined with

dry grass, capped with paver, with entrance hole

ª bird house on or near ground

² wood-dwelling solitary bees

ª leave dead twigs and stems

ª bundle hollow stems

•  pencil could fit inside

•  8” long

•  fixed in place

Flies

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most important pollinators

after bees

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like purple or white flowers,

sometimes brown or smelly

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larvae often predaceous or

parasitic

²

adults often imitate bees or

wasps

flower fly

tachinid fly male mosquito

beetles

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one of largest, oldest groups of

pollinators

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often feeding on flower itself

or on pollen, not nectar

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plants with strong, fruity smell;

minor nectar; white to greenish

flowers open during day

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large solitary flowers or

clusters of small flowers

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evolved before flies and bees

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still associated with “primitive”

moths and butterflies

² moths

ª  usually nocturnal

ª  pale flowers, strong perfume,

lots of nectar

ª  diurnal moths, too

² butterflies

ª  attracted to bright red, yellow,

orange flowers

ª  large amounts of nectar, deeply

hidden

ª  composite flowers,

inflorescences

snowberry clearwing

wasps

² about 80 species native to Pennsylvania

² major pollinators, though less efficient than bees due to hairless bodies

² predatory: adults lay eggs in living prey for larvae to eat

² social or solitary nesters ² nesting needs similar to

bees’ _{ammophila wasp}

hummingbirds

²  flowers that attract hummingbirds ª  tubes, funnels, cups

ª  red, yellow, or orange ª  odorless, open during day ª  prolific nectar producers with

nectar deeply hidden

ª  modest pollen producers that dust the bird’s head/back

²  coral honeysuckle, cardinal flower, monarda

some top plants

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ª  black cherry

ª  flowering dogwood

ª  apple/crab apple

ª  oak

ª  maple

ª  service berry

ª  redbud

²  shrubs

ª  blueberry

ª  chokeberry

ª  summersweet (clethra)

ª  dogwood

ª  viburnum

ª  fothergilla

ª  spicebush

ª  smooth hydrangea

more top plants

²  perennials

ª  mountain mint

ª  green-headed coneflower

ª  Joe Pye weed

ª  milkweed (common, swamp,

butterfly)

ª  purple coneflower

ª  cup plant

ª  Culver’s root

ª  phlox (every kind!)

ª  cardinal flower

ª  cutleaf coneflower

ª  turtlehead

²  vines

ª  coral honeysuckle

ª  American or Kentucky wisteria

²  annuals

gardening tips

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assess your site: soil

type, sun, moisture,

temperature zone

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have a plan

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start small,

then expand

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use a diversity of

plants

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plant in groups

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Penn’s Woods!

summary

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pollination is necessary for

sexual reproduction in

flowering plants

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seeds and fruit

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genetic diversity

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to attract pollinators

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provide food (native plants)

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provide water sources

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provide shelter

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safeguard habitat

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avoid toxic pesticides

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provide naturalized areas

Questions?