Barbara J. Bromley, Mercer Co. Horticulturist 2004

There is a wide variety of flowers available for the perennial garden, but when dealing with a problem soil, it becomes more difficult to select plants that are sure to survive most years. Subsoils and heavy clays can be a challenge. These are the soils on which water just sits rather than soaking into and can puddle for longer periods of time. When dry they are like brick; when wet they are sticky. The bed preparation is most important in cases like this.

A soil test is necessary to determine the amount of limestone needed to adjust acidity and fertilizers to supply plant nutrients. Coarse builder’s sand and large amounts of compost or other organic matter turned into the soil will improve both its texture and its tilth. Using the techniques of creating raised beds or berms and of double digging (working the soil to twice the normal bed depth) is also helpful. It is possible to plant some of the perennial flowering plants that follow directly into unprepared clay soil, but long term survival is less likely.

To help ensure survival of new plants, the amount of available light must be considered also. The plants listed below have been selected for sun, partial shade (ps), and shady (shade or sh) areas.

The plants listed below are just some of the perennial flowering plants that should adapt well to clay soils. Most are moderately to very pest resistant and are easy to grow. Good perennial reference books will supply additional information on propagation and maintenance requirements. Experiment to determine which are best for your sun and moisture levels.

Botanical Name Common Name






Achillea tomentosa woolly yarrow yellow Jun-Jul sun average/dry Do not overwater, tolerates poor dry soil well.Stake in windy areas. Attracts beneficials.
Achillea filipendulina fernleaf yarrow yellow Jun-Jul sun average/dry 3’, do not overwater, tolerates poor dry soil well.Good for drying. Attracts beneficials.
Arisaema spp. Jack-in-the-pulpit green/purple May-July shade moist Red berries. Great for a moist shade garden.
Aruncus dioicus goatsbeard white Jun or Jul ps/sun moist Shrub-like, 3-6’ tall. Long lived, not invasive.
Asclepias tuberosum butterflyweed orange et al Jun-Aug sun average/dry Non-invasive, drought tolerant. Attractsbutterflies and hummingbirds. Nice pods. Do notoverwater or move once established.
Astilbe arendsii & var. false spirea, astilbe white-pink-red Jun-Aug ps moist Needs moderate fertilization – a “gross” feeder.
Bergenia cordifolia heartleaf bergenia pink Apr-May s/sh adaptable 18″ tall. Large leathery leaves,
Brunnera macrophylla Siberian bugloss blue Apr-May sun/sh adaptable 12″ tall. Water in extended dry spells, does bestwith watering and fertilizing, but veryadaptable. Large heart-shaped leaves.
Echinacea purpurea purple coneflower pink Jul-Oct sun average Feed in summer. Japanese beetles may be aproblem. Very tough once established.Seeds popular with goldfinches.
Helenium autumnale‘Moerheim beauty’ Sneezewort bronze red Jul-Sept sun/ps average Water in dry weather. Support stems inexposed sites. Vigorous.
Heliopsis scabra Heliopsis yellow Jul-Aug sun adaptable Long lasting flowers
Hemerocallis spp. daylily many summer sun/ps average tomoist Water in very dry weather. Few pests.
Heuchera hyb. coral bells white-pink-red Jun-Aug sun/ps average Mulch to prevent frost heaving. Good edgingplant.
Hibiscus spp. rose mallow white-pink-red Jul-Sept sun/ps average tomoist Shrub-like. Each flower lasts one day, but openover 4-6 weeks. Japanese beetles. Bold.Use as accent plants.
Hosta spp. plantain lily lavender Jul-Aug ps-sh average Slugs and deer are problems.
Houttuynia cordata’Chameleon’ houttuynia white June sun/ps moist/wet Grown as a ground cover. May become invasive. Leavesgreen with white, pink, and red bands.
Iris sibirica, pseudo-acorus, versicolor, etc. Siberian and blueand yellowflag iris blue, violet,yellow et al. variable sun/ps average tomoist Many species adaptable to heavy soils andwet areas.
Liatris spicata gayfeather, blazingstar pinkish Jul-Aug sun/ps average Must have good drainage in winter. Attractsbutterflies and other pollinators.
Liriope muscari lily turf lavender-mauve-white Aug-Oct ps/sun average No lime. Tolerant of shade, drought, heat , andhigh humidity
Lysimachia spp. Yellow loosestrife,gooseneck loosestrife, etc. yellow-white Jul-Sept sun/ps moist Range in height from ground cover to 3′ tallVarying with species. Perfect along streamsor heavily irrigated areas.
Perovskia atriplicifolia Russian sage Lavender Summer sun average – dry 3-4 feet tall. Aromatic gray foliage.
Primula spp. primroses many Mar-Jun ps/sh moist Go dormant in hot weather. Plant in clumpsor drifts.
Rudbeckia fulgida‘Goldsturm’ Goldsturm rudbeckia yellow July-Sept sun/ps average Cut to the ground after flowering.May get powdery mildew.
Salvia spp. salvia, sage blue-violet Jul-Oct sun/ps average Gets leggy in too shady or moist soils. Verydrought tolerant.
Sedum spectabile var. stonecrop, sedum pink-red Aug-Oct sun average-dry Drought and pest resistant. Attract butterflies.
Tradescantia virginianavar. spiderwort blue-violet-white Jun-Sept sun/ps moist-dry Long-blooming. Grows almost anywhere. Formsdense clumps.
Yucca filamentosa Adams’s needle white summer sun average/dry Do not overwater. Plants are bold in textureand flower.