What Blooms When in Central Pennsylvania

May 7th, 2016

   One way to have a succession of landscape color throughout the growing season is to pick bulbs, perennials and flowering shrubs that bloom at different points in the season.

It takes some blooming knowledge and planning to have the garden look good all season.

   As the flowers of one fades, another picks up the slack and keeps the symphony going even beyond fall frost.

    The key to making it work is knowing what peaks when.

    Although each season’s weather can make a couple of weeks’ difference one way or the other, here’s a list of what typically peaks during which months in south-central Pennsylvania to help you with your spring-planting plans:

March

   * Bulbs: Crocuses, early daffodils, Iris reticulata, snowdrops, winter aconite. 

   * Perennials: Lenten rose (Helleborus).

   * Trees/Shrubs: Cornelian cherry dogwood, forsythia, Oregon grape holly, spicebush, star magnolia, sweetbox, witch hazel.

April

   * Bulbs: Crocuses, daffodils, Dutch hyacinths, early tulips, glory-of-the-snow, grape hyacinths, Grecian windflowers (Anemone), fritillaria, Siberian squill, spring snowflakes (Leucojum), striped squill (Puschkinia).

   * Perennials:  Barrenwort, bergenia, bleeding heart, bloodroot, brunnera, columbine, creeping phlox, euphorbia, foamflowers, lamium, Lenten rose, myrtle (Vinca minor), primrose, pulmonaria, rock cress,Virginia bluebells. 

Barrenwort ‘Sulphureum.’

   * Trees/Shrubs: American dogwood, bridalwreath spirea, cherry, crabapple, flowering pear, flowering plum, fothergilla, Japanese andromeda (Pieris japonica), kerria, magnolia, PJM rhododendron, redbud, serviceberry, viburnum, winter hazel.

May

   * Bulbs: Alliums, camassia, crown imperials, fritillaria, Spanish bluebells, tulips.

   * Perennials: Ajuga, amsonia, bachelor buttons, baptisia, barrenwort, brunnera, candytuft, catmint, chives, creeping veronica, dianthus, foamybells, forget-me-knot, fringe-leaf bleeding heart, geum, goats beard, hardy geranium, Jacob’s ladder, lamium, lily of the valley, meadow rue, iris, peony, salvia, snow-in-summer, sweet woodruff, Solomon’s seal, thrift, trillium.

   * Trees/Shrubs: Azalea, beautybush, Carolina silverbell, cherry laurel, chokeberry, clematis, coralberry, deutzia, fringetree, Japanese snowbell, Kousa dogwood, hawthorn, honeysuckle, horse chestnut, lilac, ornamental kiwi vine, redtwig dogwood, rhododendron, tree peony, sweetshrub, viburnum, weigela. 

June

   * Perennials: Astilbe, baptisia, bellflowers, catmint, coralbells, coreopsis, daylilies, delphinium, dianthus, gas plant, evening primrose, feather reed grass, filipendula, foxglove, foxtail lily, gaillardia, gaura, goats beard, hardy geranium, hosta, knautia, lady’s mantle, lamium, lavender, lupine, penstemon, poppies, red hot poker, rodgersia, rose mallow, scabiosa, shooting star, silene, spiderwort, tiger lilies, verbascum, veronica, yarrow, yellow corydalis, yucca.

Japanese hydrangea vine ‘Moonlight.’

   * Trees/Shrubs: Abelia, elderberry, hydrangea, Japanese hydrangea vine, Japanese spirea, Japanese tree lilac, mock orange, nandina, ninebark, potentilla, pyracantha, roses, smoketree, St. Johnswort, sweetbay magnolia, Virginia sweetspire.

 July

   * Perennials: Agastache, Asiatic and Oriental lilies, baby’s breath, balloon flowers, beebalm, black-eyed susans, blackberry lily, butterfly weed, cimicifuga, coreopsis, crocosmia, daylilies, fountain grass, gaillardia, garden phlox, gaura, goldenrod, heliopsis, hollyhock, hosta, Jupiter’s beard, liatris, obedient plant, persicaria, purple coneflower, veronica, red hot poker, Russian sage, sea holly, shasta daisy, silphium, soapwort, stokesia, veronica, veronicastrum.

   * Trees/Shrubs: Abelia, butterfly bush, clematis, roses, crape myrtle, goldenrain tree, rose-of-sharon, summersweet (Clethra), stewartia.

August

   * Perennials: Agastache, aster, black-eyed susans, cardinal flower, garden phlox, goldenrod, hardy hibiscus, heliopsis, hosta, Japanese anemone, Joe Pye weed, leadwort, ligularia, liriope, miscanthus, monkshood, perennial sunflower, purple coneflower, reblooming daylilies, Russian sage, sedum, sneezeweed, switchgrass, turtlehead, veronica, yarrow.

   * Trees/Shrubs: Beautyberry, blue mist shrub (Caryopteris), butterfly bush, crape myrtle, rose-of-sharon, seven son flower (Heptacodium), tree hydrangea, vitex.

Seven son flower in bloom.

September

   * Bulbs: Dahlia, fall crocus (Colchicum), lycoris.

   * Perennials: Agastache, aster, boltonia, catmint, gaillardia, gaura, goldenrod, Japanese anemone, Joe Pye weed, lavender, leadwort, liriope, mums, reblooming daylilies, Russian sage, salvia, sedum, toad lily, turtlehead.

   * Trees/Shrubs: blue mist shrub (Caryopteris), butterfly bush, roses, reblooming hydrangeas, sweet autumn clematis.

October

   * Perennials: Aster, catmint, gaillardia, goldenrod, mums, Nippon daisy, salvia, sedum.

   * Trees/Shrubs: Blue mist shrub (Caryopteris), reblooming hydrangeas, roses.

Strategies for Spreading Out Seasonal Interest

   1.) Add more variety. Plant more plants and different kinds of them. You’ll get multi-season change and interest just by dumb luck.

   2.) Make a conscious effort to plan for all four seasons. If you can’t do the above “buck-shot” approach, think what each part of the yard will look like in each season and seek out plants that will add interest to those boring gaps.

   3.) Move beyond 2-week wonders. Many of our over-used favorites are one-dimensional plants that peak only for a few weeks out of the whole year (azaleas, rhododendrons, lilacs, peonies, forsythia, burning bush, for example).

   4) Look for hard-workers – plants that do more than one thing in one season. Example: oakleaf hydrangea, which blooms white in late spring, gets burgundy foliage in fall and then shows off peeling bark when the leaves drop for winter.

   5.) Don’t plant-shop only in May. You’ll tend to buy only what’s looking good then… or on sale. Shop in different seasons. Make it a point to go whenever your yard is looking particularly barren.

   6.) Visit public gardens. They’re great for getting ideas and seeing what’s doing what at any given time. Visit these in different seasons, too.

   7.) Pay attention to what other people have planted. If you see plants nearby doing something interesting at a time when your yard is snoozing, find out what those plants are and add them to your list.