Container Gardening for Earth Renewal
Growing native plants in containers is surprisingly easy and provides plenty of useful wildlife habitat. Bees, butterflies, and hummingbirds will happily find your balcony. Imagine the potential if every city dweller with a front stoop or balcony put out containers with native plants!
If you live in a neighborhood with high deer or rabbit pressure, your deck might be the place to grow those more vulnerable plants you have been yearning for.
Containers can bring needed height to a garden bed or a woodland path. They can also elevate and showcase small species that might otherwise get lost in a fully planted setting.
A few easy plant combinations for a medium sized pot (1-2 feet in diameter)
Spring - Moss Phlox, Foxglove Beardtongue, Blue-eyed Grass (Phlox subulata, Penstemon digitalis, Sisyrinchium angustifolium)
Summer - Orange Coneflower, Switchgrass, Yarrow (Rudbeckia fulgida, Panicum virgatum, Achillea millefolium)
Fall - Aromatic Aster, Muhly Grass, Rough Goldenrod ‘Fireworks’ - (Symphyotrichum oblongifolium, Muhlenbergia capillaris, Solidago rugosa ‘Fireworks’)
For shade or part shade
Spring - Woodland Phlox, Fringed Bleeding Heart, Blue-eyed Grass (Phlox divaricata, Dicentra eximia, Sisyrinchium angustifolium)
Summer - Blue Mistflower, Great Blue Lobelia, Pennsylvania Sedge (Conoclinium coelestinum, Lobelia siphilitica, Carex pensylvanica)
Fall - Northern Maidenhair Fern, Blue Mistflower, Coral Bells (Adiantum pedantum, Conoclinium coelestinum, Heuchera americana)
For sun - Butterfly Weed, Thread-leaf Coreopsis, Wild strawberry, Spike Gayfeather (Asclepias tuberosa, Coreopsis verticillata, Fragaria virginiana, Liatris spicata)
For part sun - Dwarf Crested Iris, Foxglove Beardtongue, Beebalm, Purple Giant Hyssop (Iris cristata, Penstemon digitalis, Monarda didyma, Agastache scrophulariifolia)
Aromatic Aster, Muhly Grass, Rough Goldenrod
Wild Bleeding Heart
Choosing pots & potting mix
Most of the plants in the Native Plants for Northern Virginia guide can bloom in a pot, and probably overwinter if conditions are right. Here are some basic tips:
Choice of pots: The larger the pot, the less risk there is from deep freezes. Ceramic pots breathe and improve drainage but can crack in the winter; terra cotta is particularly prone to cracking. Plastic pots are sturdier. Dark colored pots may overheat the roots. Do not put rocks at the bottom: paradoxically, this practice actually decreases drainage.
Potting mix: Unlike growing annuals from seed, it is unnecessary to use sterile potting medium. You may use regular gardening soil but should lighten it by using at least half potting mix or compost. The plants will use up the nutrients, so adding compost or fertilizer may eventually become necessary..
For a much more detailed discussion of the above points and many others, see this excellent resource by Leigh Pickering published by the Audubon Society of Northern Virginia: Captivating Containers with Native Plants.
To maximize the chance of overwintering, it is recommended that you choose plants that are adapted to a hardiness zone two zones colder than where you are. (Most of Northern Virginia is in Hardiness Zone 7a. Part of Loudoun County is in Zone 6b.) As it happens, many of our plants are adapted to Zone 4 or 5 as well, but for more tender plants, sheltering them in winter next to a south-facing wall might help. The main problem with overwintering is not the temperature but the wet: many plants cannot tolerate
Grasses can do well in a pot, but their roots might crowd out other plants.
Several online and word-of-mouth sources reference native plants that are particularly suitable for containers, though they do not explain what criteria or experience they used. Below is a compilation of some of these recommendations.
Remember - always base your purchases on the scientific name! Many plants share the same common names.
Sun or part sun
Allium cernuum (Nodding Onion)
Asclepias incarnata (Swamp aster)
Asclepias tuberosa (Butterfly Weed)
Chasmanthum latifoliim (River Oats) - watch those seeds!
Conoclinium coelestinum (Blue Mistflower)
Coreopsis verticillata (Threadleaf coreopsis)
Eupatorium dubium (Joe Pye Weed) - don’t let it dry out.
Fragaria virginiana (Wild strawberry) - “spiller”
Helenium autumnale (Sneezeweed)
Iris cristata (Dwarf Crested Iris)
Lonicera sempervirens (Coral Honeysuckle (with a big trellis)
Monarda punctata (Spotted Beebalm)
Panicum virgatum (Switchgrass)
Passiflora incarnata (Purple Passionflower)
Penstemon digitalis (Beardtongue)
Phlox paniculata (Garden Phlox)
Phlox subulata (Moss Phlox)
Rudbeckia fulgida (Orange Coneflower)
Switchgrass (Panicum virgatum)
Schizachyrium scoparium (Little Bluestem)
Solidago rugosa ‘Fireworks’ (Rough Goldenrod)
Symphyotrichum ericoides (Heath Aster)
Symphyotrichum oblongifolium (Aromatic Aster)
Tradescantia virginiana (Spiderwort)
Yucca filamentosa (Adam’s Needle)
Orange Coneflower (Rudbeckia fulgida)
Switchgrass (Panicum virgatum)
Great Blue Lobelia, Hairy Alumroot, Pennsylvania Sedge
Adiantum pedatum (Northern Maidenhair Fern)
Aruncus dioicus (Goatsbeard)
Dicentra eximia (Fringed Bleeding Heart)
Dryopteris marginalis (Marginal Shield Fern)
Elymus hystrix (Bottlebrush Grass)
Heuchera americana (Coral Bells)
Matteuccia struthiopteris (Ostrich Fern)
Polystichum acrostichoides (Christmas Fern)
Sedum ternatum (Three-leaved Stonecrop)
Tiarella cordifolia (Foamflower) - for a “spiller”
Clethra anilfolia (Summersweet)
Hydrangea arborescens (Smooth Hydrangea) - don’t let it dry out
Hypericum prolificum (Shrubby St. John’s Wort)
Ilex glabra (Inkberry)
Itea virginica (Virginia Sweetspire)
Rhus aromatica (Fragrant Sumac)
Containers without drainage holes
Sun or Part Sun:
Hibiscus moscheuotos (Swamp Mallow) - large container
Iris virginica (Southern Blue Flag)
Juncus effusus (Common Rush) - wet containers or water gardens
Mimulus ringens (Allegheny Monkeyflower)
Equisetrium hyemale (Rough Horsetail) - wet containers or water gardens (Full sun to shade)
Osmundastrum cinnamomeum (Cinnamon fern) - Be sure to keep it from drying out.
Eastern Red Columbine
Yarrow, Blue Lobelia, New England Aster 'Purple Dome', Carolina Jessamine vine, Purple Coneflower (a native of the prairies)
Striped Cream Violet (Viola striata)