Planting Perennials for Pollinators: A Tennessee Gardener's Guide
The basic approach is to plant a mix of Southeast native perennials that bloom at varying times in full sun and well-drained soil‚ so these pollinators (bees‚ butterflies and hummingbirds) will visit the garden from April through October․ The longer version‚ the one that will get you that busy garden‚ concerns which plants to choose that will flourish in the Tennessee climate and how pollinators use those plants at every stage of growth‚ not just when they're in bloom․
Why are perennials better? Because they have established root systems․ A coneflower that got planted two years ago will come back in March with roots that are in place to put out leaves and flowers a full month or more before an annual would even germinate in the ground․ That early start is timed right for early-emerging‚ native bees and the first monarchs that are migrating north․
Why Tennessee's Climate Actually Works in Your Favor
Most of Tennessee falls into USDA zones 6b to 7b‚ with some areas of zone 8a in the western part of the state near Memphis․ This almost precisely overlaps the native range of the most common pollinator perennials on the market․ Now‚ milkweed‚ coneflower‚ beebalm‚ and blazing star all originated in this zone or one very similar to it․ You're not fighting the plant's natural preferences; you're working with them․
Planting perennials from September to mid-November is ideal․ Soil temperatures remain warm long after the air temperature has dropped․ This means that perennials are already growing roots during the winter‚ and getting a jump on the summer heat․ Spring planting is fine too‚ but will require more attention to watering that first summer․
Core Perennials Worth Planting
Milkweed is the most important host plant for monarchs․ Without it‚ monarch caterpillars cannot survive as they only eat these plants․ Two species that are good to establish during Tennessee summer include common milkweed (Asclepias syriaca) and butterfly weed (Asclepias tuberosa)․ Butterfly weed does better with dry soil and drought․ Butterfly weed prefers sun‚ and generally doesn't form flowers until the second year․ Don't be alarmed if caterpillars eat the leaves; this is what the plant is supposed to do․
Purple coneflower (Echinacea purpurea) is about as forgiving as perennials get․ It will tolerate clay soil‚ which describes a lot of Middle Tennessee yards‚ and bloom from June into September if you deadhead spent flowers․ It's best to leave some seed heads after winter‚ where the goldfinches can eat them‚ and where native bees can overwinter․
Beebalm (Monarda) attracts hummingbirds as well as bees and butterflies․ It is worth growing for its fragrance alone․ It spreads by rhizomes and should be planted with sufficient room to grow‚ or clumps should be divided every three to four years․ If air circulation is poor‚ powdery mildew can be a problem in humid Tennessee summers‚ therefore, plant 18 to 24 inches apart‚ not close together․
The blazing star (Liatris spicata) is another flower most gardens lack for late-season nectar․ By August‚ all the spring flowers have gone to seed‚ but the purple spikes of blazed star are at their peak․ The flowers are an important food source for butterflies preparing for migration and for bees stocking up on food in preparation for winter․ They grow best in well-drained soil‚ which is necessary for dense clay-heavy soils․
Inconspicuous‚ jewelweed is good for wet‚ shady areas that are not well-suited for other pollinator plants: along a fence‚ outside a downspout‚ or at the edge of a wood․ The orange trumpet-shaped flower is highly attractive to hummingbirds․ The sap is used in folk remedies to treat poison ivy irritation of the skin․ According to other sources‚ the plant is good for a wet and shady area of the yard where nothing else seems to want to grow․
For added volume‚ include black-eyed Susan for its long bloom time and reliable self-seeding‚ and Joe Pye weed where you've got lots of ground to cover and headroom to spare (five feet tall‚ one plant brings a late summer mass of dozens of swallowtails)․
Planting and Spacing That Actually Works
Dig holes no deeper than the container but twice the width of the root ball ․ One of the most common planting mistakes with perennials is planting too deep․ Backfill with native soil‚ not an amended potting mix‚ so roots can grow into native soil․ Water well immediately after planting‚ and two to three times a week for the first month․ Watering frequency can be reduced as roots develop․
Space plants according to their full-grown width‚ not how small they appear in a one-gallon pot․ Coneflower and beebalm both desire 18 to 24 inches between plants‚ for example․ Planting too close together causes poor airflow‚ which causes more fungal disease‚ common in humid Tennessee summers․
Designing for Continuous Bloom
A pollinator garden that only blooms in June isn't doing pollinators much good the rest of the year․ Try to get something blooming from early spring to the first hard frost․ The milkweed and beebalm fill the early to mid-summer‚ the coneflower heads run into late summer‚ and the blazing star and Joe Pye weed carry us to September and October․ This succession of bloom is more important than any one plant․
Do not use pesticides‚ even organic or controlled ones‚ which may kill not just the target species‚ but also bees and butterfly larvae․ Do not over-mulch or tidy in autumn․ Leaving plant debris and hollow plant stems can provide spaces for native bees to overwinter․
Getting Started
The TN Nursery sells milkweed‚ coneflower‚ beebalm‚ blazing star‚ and jewelweed as established perennial plugs and potted plants grown in the Southeast rather than shipped in from another climate zone․ These plants will thrive in this climate with the lowest transplant shock and quickest establishment, which means blooming and pollinator activity can happen as soon as possible․
The few that you plant this fall‚ or next spring‚ will transform your yard‚ but not until next year and the following․
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