Problem-Solving Perennials for Challenging Sites

Deep shade, dry soil (such as you might find under a mature maple):

Asarum  canadense (Canadian wild ginger) – Kidney-shaped leaves to 6” tall. Maroon-brown, bell-like flowers hide under the leaves.  Great in  woodland gardens. No winter presence. Zone 3, eastern U.S. native.       

Epimedium  (Barrenwort, Bishop’s cap) – Tolerate deep shade and dry soils well. Clump-forming perennial ground cover. 7-12” tall, 10-12” wide. Flowers available in a wide range of colors. Will grow in full sun, but not wet soil. Zone 5.

Helleborus x orientalis (Lenten rose) – Incredible variety of flower colors and forms now available. One of the few truly evergreen perennials. Prefers moisture, but will tolerate dry soils.12-15” tall, at least that wide. Slow growing. Zone 5. 

Full sun, hot site (lots of reflected heat from walls, paved surfaces):

Allium ‘ Millennium’ (Flowering onion) – Strap-like foliage is glossy, the plants reaching 1’ tall and equally wide.  1.5” - 2” dia. rose-purple globes literally last a month starting in mid-late summer. Sterile, no surprise seedlings popping up.  Deer and rabbit-proof . Zone 5.  

Asclepias  tuberosa (Butterfly weed) – Yes, this is one you want for Monarch butterflies! Adults love the flowers for the nectar, while the larvae feed on the leaves. Flower color can be variable: orange, yellow or orange-red and last up to 6 weeks. Zone 5, U.S. native.    

Geranium x cantabrigiense ‘Biokovo’ (Cambridge geranium, Cranesbill) – An 8” tall evergreen perennial. Pretty lobed leaves are aromatic and turn multiple fall colors of gold, purple and red. The flowers are white and pale pink (1” dia.) in late spring. Best used as a front-of-border plant or edging plant along paved surfaces. Zone 5.

Periodic flooding (standing surface water multiple times during the year):

Carex (Sedges) – Broad, grass-like blades that can be erect, but most often arch and reflex like a fountain. Huge family with varying heights and spreads. Will toleratelearte Ill    

Hibiscus  moscheutos  (Rose mallow, Hardy Hibiscus) – While late to emerge it makes a 3’-5’ shrub by summer’s end. Dinner plate-sized flowers  start in July and go into fall. Each flower lasts one day. Wide range of colors. Zone 5, eastern U.S. native.     

Ligularia ‘Britt-Marie Crawford’ (Leopard plant) – Will perform admirably in the doubly challenging sites of flooding and considerable shade! Actually wants wet feet. Glossy purple-black leaves on a plant 2’-3’ tall and 2’ wide. Flowers are orange-yellow and daisy-like in mid-summer. Deer tolerant, slug-susceptible. Zone 4.

Osmunda regalis (Royal Fern) – A fern that will tolerate full sun if its roots are wet. Can get 3-4’ tall and equally wide with moisture and lots of organic matter. Pretty rust fall color. Zone 4.

Varmint resistant  (both deer and rabbits):

Astilbe sp. (Astilbe) – Huge range of height, color and plant size choices. Whites, pinks, rose-reds, even salmon June -July. Partial shade is preferred, but can do full sun with even soil moisture. Dried seedheads can be left on to extend the season of  “interest”. Nice fernlike foliage. Can be Zone 4 or 5, depending upon species.

Calamintha nepeta spp. nepeta (Calamint) – Slightly hairy leaves, minty fragrance.This 15-18” perennial flowers its heart out from late August until frost. Weeks and weeks of lilac and white flowers up and down the stem attract bees like crazy. Sun, well-drained. Fine textured and subtle, use in groups of  3 – 5, or more. Zone 5.     

Rodgersia (Rodger’s flower) - Totally unattractive to 4-legged garden interlopers, this plant also is great for partial shade and very moist soils. In those conditions can reach 3-5’ tall and wide. Leaves have amazing texture that is almost tropical. Great pondside or near any water feature. Flowers are primarily white or rose-red (depends upon species). Zone 5.   

Clay busters (for the densest, most difficult soils):

Baptisia australis (False indigo) – The emerging tips look like purple asparagus. Foliage is gray-green with an interesting texture. The flowers look like lupines and now come in a range of colors. Makes a shrub 3-4’ tall, 3’ wide. At least ½ day sun, more is better. Zone 4, U.S. native.  

Liatris cv. (Spike Gayfeather) – Very linear, vertical plant with beautiful mauve flower spikes in summer. Long-lasting flowers are unique in that they start blooming from the top down. Attracts butterflies and makes a long lasting cut flower. Needs deadheading. Dwarf varieties like ‘Kobold’ don’t need staking at 18-24” tall. Sun. Zone 3, central U.S. native.

Panicum virgatum  ‘Northwind’ (Switchgrass) – One of the more columnar grasses and it hasn’t been overused. Leaf blades are broader than most Switchgrasses and a nice blue-green cast. Yellow-beige flowers appear in late summer bringing total plant height to almost 6’. Sun. Use in masses of at least 3 - 5 to get a strong effect. Zone 5, U.S. native.          

Tall screening:

Eupatorium  maculatum  (Joe-pye weed) – Grows quickly to 5-6’ tall and 3-4’ wide . Long-lasting domed flowers of reddish-purple in late summer dry to fluffy brown. Dark green foliage that suits the strong character of the plant without being coarse. In full sun, self-supporting, so no staking needed.  Dwarf selections are available. Zone 3, eastern U.S. native.

Filipendula rubra ‘Venusta’ (Queen-of-the-Prairie) – Nearly identical in size to Joe-pyeweed at 5-7’ tall and 3’ wide. Lighter green foliage that is lobed. Beautiful peach-pink flowers in midsummer are very showy. Can even do light shade. In full sun, needs even moisture. Great for wet soils. Zone 3, eastern U.S. native.    

Rudbeckia  nitida ‘Herbstonne’  (‘Autumn Sun’ coneflower) – Dazzling with 7’ height and 3’ wide. Bright golden-yellow daisies that reflex like badminton birdies. Flowers are effective from August-October. Loose staking early in the season might be a good idea. Seedheads are great food for birds. Zone 5, southern U.S. origin.  

Evergreen foliage:

Bergenia cordifolia (Heartleaf Bergenia) – Thick, bright green foliage that resembles young cabbage. In spring, deep pink flowers on spikes that stand just above the foliage. Foliage fires maroon-burgundy in late fall. Full sun (with moisture) or partial shade. 12-15” tall, spreads slowly to make “colonies”.  Spring leaf removal /tidying up will be necessary. Zone 4.     

Heuchera cv. (Coral bells) – Evergreen, lobed leaves arranged in mounded ground-hugging rosettes. Partial shade is generally preferred. Grow for the foliage rather than the flowers. Well-drained soil is a must, particularly for the winter. Zone 4.    

Iberis sempervirens  (Evergreen Candytuft) – Mat-forming evergreen perennial noted for its long-lasting early spring bloom. Just a great and underused edging, border or rock garden plant. 6-10” tall, 18” wide. Must prune hard immediately after bloom. Full sun. Zone 3.    

Alternative ground covers:

Ajuga reptans ‘Black Scallop’  (Bugleweed) – Love the texture and the purple-black foliage. Foliage is semi-evergreen depending upon the winter exposure. Blue-violet flower spikes in late spring (bees love them). Foliage is only 2-3” tall and spreads quickly. Looks particularly good as a facer for gold, chartreuse or lime-green foliage. Zone 3.          

Carex elata ‘Bowles Golden’  (Tufted sedge) – Softly arching bright gold leaves with slight green edges light up partial shade to full sun sites. Color softens later, especially in summer heat. Loves moist soils. Flowers are inconspicuous. 15-18” tall and wide, clump-forming. Zone 5.      

Hakonechloa macra (Japanese forest grass) – Incredibly graceful arching perennial, whether the green species or the beautiful variegated forms. Light to moderate shade and evenly moist soil yield best plants. Not aggressive. Flowers aren’t ornamental. All varieties become straw colored in the fall. Zone 5.        

Unique foliage texture or color:

Aruncus aethusifolius  (Dwarf goat’s beard) – A perfect little mound of finely cut, deep green foliage. Creamy white flowers (resembling Astilbes) float over the top in summer. Hints of burgundy and gold fall color even in shaded sites. Partial/full shade. Use in masses at front of border. 8-10” tall, 15” wide. Zone 4.

Molinia caerulea ‘Variegata’ (Variegated Moor grass) – Beautiful clumping ornamental grass with narrow, creamy yellow-white leaves. Summer flowering brings bright yellow stalks with open, airy flower heads. No particular winter presence. Full sun, partial shade. 24” tall. Zone 4.   

Mukdenia rossii  ‘Crimson Fans’ – Clump-forming perennial with unique toothed leaves, perhaps 12” tall. Leaves emerge green, then develop bronze-red streaks by summer. Bell-like white flowers on a spike above the foliage in spring. Sun or partial shade. Great for woodland or naturalized perennial border. Zone 4.