Monday, July 14, 2014

A Pollinator Border

When I planned my new vegetable garden last year I included a double fence design to help keep out the deer.  At the outer fence I planned for a border of pollinator-friendly native plants.  This border would help attract pollinators to the garden and also provide shelter for predatory insects to hang out.  By providing cover for the predators, damage due to insect pests is significantly reduced without the use of pesticides.

The border around the garden has a variety of native plants.  A bluebird is currently nesting in the box,
I try to avoid walking by, but it happens

The plants for this border need to provide pollen or nectar for the pollinators, be low maintenance, bloom sometime during the growing season and be somewhat to very resistant to deer browsing.  I also looked for plants that might deter smaller mammals that could burrow into the garden.  The garden location is in full sun and can get dry. 

Plants that are native to the area are the best choice for a pollinator garden.  These plants are natural food sources for the native insects that will be doing most of the work.  It is nearly impossible to find a single plant that will bloom the entire garden season, so a mixture of plants with staggered blooming times will provide some food for insects throughout the season.  The Xerces Society has guidelines for creating a pollinator friendly garden.  

When I put in the garden last year, most of the pollinator plants I put in were liners or seedlings.  Being young and of small size, they did not mature enough to bloom.  With a year in the ground they are really looking good now.  Here's a listing of plants I used in by pollinator border.

The earliest blooming plant in the border was Wild Columbine, Aquilegia canadensis.  The nodding red and yellow flowers are attractive to hummingbirds.  Blooming period is typically April through May.  The seeds are held loosely in the upright pods.  

I did not get a photo of my Columbine this season, but here you can see
the seed pods mixed in with some Black-eyed Susans.  I need to shake out
the seed pods to get more plants for next year.

Last year I planted both black-eye and Brown-eyed Susans (Rudbeckia hirta and R. triloba).  The deer were constantly eating the flowers and leaves of both species.  This year only the Black-eyed Susans returned.  I have been more diligent about spraying them with hot pepper solution, which seems to work.  While not as upright as Yellow Cone Flower (R. fulgida) I like the extended blooming season of R. hirta, lasting from June through September.

Here's Spotted Beebalm in a mixed border of Black-eyed Susans and False Pennyroyal.
The flowers are actually small yellow tubes hidden by the large pinkish bracts.
Spotted Beebalm, Monarda punctata, was grown from seed and actually matured enough to bloom the first year.  This year it really went to town.  Peak blooming season is June and July.  This plant is very resistant to deer browsing and attracts mostly bees and wasps.

This is a short-lived perennial so it needs to set seed to maintain a presence in the garden.

The flowers of Wild Bergamot are more exposed than Spotted Beebalm's
 making it easier for large butterflies to access them.
Another member of the Monarda genus in the garden is Wild Bergamot, M. fistulosa.  This is a much taller species, easily over 4 feet in this garden.  The flowers attract bees, butterflies and hummingbirds.  The bloom time is from early July through August.

These two Monarda species do well in dry to medium soils.  If the soil were moister Oswego Tea, M. didyma, would be a good choice, as well.

I had a difficult time with deer munching on the young Butterfly Weed, Asclepias tuberosa, plants last year.  This year they are doing much better and are coming into full bloom now (early July).
I have not seen any Monarch butterflies around these milkweeds,
mostly small greenish bees (Sweat bees?)

I have established a dense hedge of American Pennyroyal
 along one edge of the garden.
We'll see if it keeps out the moles, etc.
One of the first native annuals I put around the garden was American or False Pennyroyal, Hedeoma pulegioides.  This diminutive member of the mint family has a strong minty scent when touched.  It can act as a repellent for some insects, possibly mosquitoes.  I am interested to see if it will also discourage deer and small mammals from entering the garden.  Direct seeding in the garden last spring gave few plants, but these seeds came up in full force this year.  Despite what it says on the seed packet, fall sowing of some moist stratification (30 days, moist at 35-40 F) helps break seed dormancy.
I'm pretty sure this is one of the Nodding Onions.
I'll know better once it reaches full bloom -
will the flower continue to droop or turn upright.

Another plant to help form a barrier to invasion by burrowing mammals is Alliums.  I planted a long row of Nodding Onions, Allium cernuum, in the border. The idea is that they will be repelled by the presence of the onion bulb underground.  I've seen a few come up in the mix of plants, but sometimes they are hard to tell from the stray grasses also in the garden.  As we get later into blooming season (June-August) they should be easier to pick out.  

In the garden there is some white Yarrow, Achillea millefolium, that just blew in.  I also added a more colorful cultivar call 'Strawberry Seduction' to jazz things up a little.  I had problems last year with deer browsing, but not so this year.  Is this due to a more mature plant, or is it random choice by the deer?

I don't usually go for the flashy cultivars, but
I wanted to add some more red to the garden
The middle of the garden provides a refuge
for the more deer-sensitive species.

In the center of the garden I put a ring of tall flowers that was meant to draw the pollinator further into the garden.  Since these are more protected from deer, they don't have to be so deer resistant.  This year I have some Purple Cone Flower (Echinacea purpurea), False Sunflower (Heliopsis helianthoides 'Summer Sun', Beach Sunflower (Helianthus debilis 'Pan') and 'Autumn Beauty' Sunflower (Helianthus annuus).  The first two species bloom for the first half of summer and the sunflowers carry the load into the fall.

I selected the 'Autumn Beauty' cultivar of sunflower because it only grows to 6 feet, keeping it in scale with the rest of the plants and reducing the risk of tipping over.

My deer really like to eat various species of Helianthus, so I could not grow these in unprotected areas.  I'm not sure how they would treat the False Sunflower, but I'm sure they would give it a taste.  

Daisy Fleabane (Erigeron annuus) and Heal-all (Prunella vulgaris) are a couple of indigenous plants that have found a welcome place in this border.  Heal-all is edible (haven't tried it) and has many herbal/medicinal applications.  It can be used as a native ground cover, growing between 2 and 12 inches tall.

Heal-all is widely disbursed through the Northern Hemisphere.
It is a larval host for the Clouded Sulphur butterfly.

In the new part of the border I'm trying some new native annuals.  I have grown Sulphur Cosmos, Cosmos sulphureus, by direct sowing in Boston before.  It did germinate well in the border here, but has since disappeared.  I also sowed some Plains Coreopsis, Coreopsis tinctoria, in the same area.  Germination wasn't as good, but the plants are persisting.  In another area the deer sampled the Coreopsis, but did not actually eat it.  Another native Coreopsis species that could be used in the border is Threadleaf Coreopsis (C. verticillata).  It is easy to care for and fairly resistant to deer.

Plains Coreopsis starts out kind of wiry, but straightens up as it matures.

 One additional note about the border.  My outer fence is a 5-wire electric fence, but it is not energized.  If it were, it would immediately ground out because of all the plants growing on the wires.  If you have an energized fence it must be free of plants.  A flowering border should be sited well inside or outside the electrified wires.


Leah said...

Your pollinator-friendly border sounds like a great idea and looks so pretty. I've had trouble with zucchini not getting pollinated (and then trying to hand pollinate it myself), so something like this might help. However, do you worry about the taller flowers shading your garden?

Curtis said...

Since the border is about 3 feet from the vegetable rows shading is not too much of a problem. However where the Monarda is over 5 feet there is the beginning of an issue.