Climate Change and Resilient Perennials

Climate change, with its variations in temperature, unpredictable rainfall and extreme weather events, is disrupting the growth, flowering and fruiting cycles of the plants in our gardens. These conditions also increase their vulnerability to disease, pests and water stress due to drought or heavy rainfall. Perennials, in particular, may be less tolerant of climate change than annuals, shrubs and trees.

Vulnerability

Perennials, with their less robust roots and stems, are more vulnerable to extreme conditions such as high winds and flooding. Unlike trees and shrubs, which accumulate resources in their woody structures, perennials store their reserves in underground parts such as rhizomes and bulbs, which may not be sufficient in the face of harsh or unpredictable winters. Shrubs and trees, with their deep roots and longevity, can draw water from deep underground and withstand the vagaries of the weather. As for annuals, they complete their life cycle in a single season, avoiding adverse conditions and adapting rapidly each year.

Although perennials are generally more vulnerable, some stand out for their resilience, especially native species. I have selected 8 perennials that are particularly resistant to the extreme conditions brought about by climate change. To do this, I established 10 essential criteria to guarantee their resilience, and these perennials all scored a perfect 10 out of 10.

Selection Criteria

1. Hardiness: Good hardiness enables plants to survive and thrive in variable and extreme climatic conditions.

2. Flexibility to soil and light: Adaptability to different soils and light conditions enables plants to grow in a variety of environments, which is essential when soil and sunlight conditions change.

3. Drought tolerance: Drought tolerance helps plants to survive prolonged periods of low rainfall, which are becoming increasingly frequent.

4. Flood resistance: Flood resistance enables plants to survive in conditions of heavy rain and flooding, phenomena that are becoming more common.

5. Wind tolerance: As extreme weather conditions, including high winds, become more frequent, wind tolerance becomes important. Wind-tolerant plants are less likely to suffer physical damage.

6. Heat tolerance: Tolerance to heat enables plants to survive and grow despite rising average temperatures and more frequent and intense heat waves.

7. Cold resilience: The ability to withstand cold is crucial for plants in regions where temperatures can drop significantly, enabling them to survive episodes of extreme cold.

8. Disease resistance: Disease resistance is essential, as climate change can encourage the spread of new diseases and pests.

9. Non-invasive or native: Native plants integrate better into local ecosystems without disturbing existing species. They are better adapted to local conditions and contribute to ecological stability. If cultivated exotic plants are chosen, prefer those that are non-invasive.

10. Pollinator-friendly or wildlife-supporting: Plants that are pollinator-friendly or wildlife-supporting help maintain biodiversity and healthy ecosystems, which in turn support plants. They provide crucial habitats and food sources for pollinators and other species, which are also affected by climate change.

8 Resilient Perennials

Milkweed (Asclepias tuberosa)

Tuberous milkweed is a perennial plant native to North America, renowned for its remarkable resilience to climate change. It is distinguished by its bright orange flowers, as well as being drought-resistant. Tuberous milkweed thrives in well-drained soils and tolerates poor soil conditions, making it ideal for a variety of garden environments, even those with low fertility. Its ability to survive in drought conditions and its low water requirement make this plant an excellent choice for gardens that are sustainable and resistant to climate change.

In addition to its aesthetic appeal, tuberous milkweed plays a crucial ecological role, providing habitats and food sources for a variety of pollinators. It blooms from June to August, providing a long season of color and life in the garden. With little susceptibility to disease or pests, this plant is a robust, reliable option for gardeners looking to create a resilient, eco-friendly outdoor space.

Some recommended varieties: A. tuberosa ‘Hello Yellow’, A. tuberosa ‘Gay Butterflies’, A. tuberosa ‘Western Gold Mix’, A. tuberosa ‘Orange Crush’, A. tuberosa ‘Soulmate’.

Tickseed (Coreopsis)

The Coreopsis genus, comprising 35 species mainly native to North America, is renowned for its resilience in the face of climate change. These plants, which range from annuals to perennials, are particularly well adapted to a variety of climates, making them ideal for climate-resilient gardens. Coreopsis thrive in full sun and tolerate poor, well-drained soils. Their ability to survive and flower even in difficult conditions makes them an attractive option for gardeners looking for robust, long-lasting plants. Flowering from June to October, they provide a colorful spectacle that attracts pollinators.

Most coreopsis species are easy to propagate by seed, stem cuttings or division, so their presence in the garden can be maintained without undue effort. The most enduring species, such as C. auriculata and C. verticillata, can live for more than 10 years, while some, like C. tripteris, are virtually eternal. The diversity of species and hybrid varieties offers gardeners a multitude of choices, whether they’re looking for yellow, orange or even pink flowers.

Some recommended varieties: C. auriculata ‘Nana’, C. grandiflora ‘Early Sunrise’, C. grandiflora ‘Presto’, C. verticillata ‘Moonbeam’, C. verticillata ‘Zagreb’.

Echinacea (Echinacea)

Echinacea, belonging to a small genus of nine species native to North America, is a hardy and versatile herbaceous plant, perfect for modern gardens. This plant forms a dense rosette of dark-green, often oval leaves, and in summer and autumn produces sturdy flower stems bearing large, daisy-like flowers. Echinaceas are particularly well adapted to changing climatic conditions, tolerating rich, moist soils as well as periods of drought. They prefer full sun, but can also thrive in semi-shade.

Thanks to their hardiness (zone 3 or 4, depending on the species), they can survive harsh winters and withstand summer heat. Echinaceas are rarely affected by disease or insects in our climate. They attract butterflies and granivorous birds, but are not invasive. What’s more, they are easily multiplied by division or seeding, and their long life makes them an excellent plant for beginners and experienced gardeners alike.

Some recommended varieties: E. purpurea ‘Magnus’, E. purpurea ‘Ruby Star’, E. purpurea ‘White Swan’, E. purpurea ‘PowWow Wild Berry’.

Joe-Pye Weed and Boneset (Eutrochium and Eupatorium)

Once neglected, Joe-Pye weed and boneset are gaining in popularity due to their ornamental appeal and resilience to climate change. These native North American plants prefer rich, moist soils, but also tolerate drought once established. They attract butterflies and are rarely affected by disease or insect pests.

Once part of the Eupatorium genus, Bonesets are now divided between it and the Eutrochium genus. Bonesets are distinguished by their feathery inflorescences of tubular flowers, often fragrant and much appreciated by butterflies. After flowering, the downy seeds keep the plants attractive well into winter. Most species flower in late summer or autumn and grow in clumps with a flared habit. They can be propagated by division, stem cuttings or seed.

Thanks to their hardiness and adaptability, these plants are an excellent choice for gardens that are resistant to climate change. They are ideal for beds, naturalization and wetlands.

Some recommended varieties: Eutrochium maculatum groupe Atropurpureum ‘Gateway’, E. maculatum groupe Atropurpureum ‘Little Red’, E. maculatum groupe Atropurpureum ‘Phantom’, E. dubium ‘Little Joe’, E. dubium ‘Baby Joe’, E. fistulosum ‘Joe White’, E. fistulosum ‘Ivory Towers’, Eupatorium fortunei ‘Pink Frost’, E. cannabinum ‘Flore Pleno’, E. perfoliatum.

Dense blazing star (Liatris spicata)

Dense blazing star is a perennial appreciated for its resilience and adaptation to varied climatic conditions. Native to northeastern North America, this species is particularly well adapted to damp, semi-shaded environments, hence its nickname marsh blazing star. However, it also adapts well to flowerbed conditions and, once established, tolerates drought.

Dense blazing star is characterized by its mauve, bottlebrush-shaped spikes, borne on sturdy stems, which add a colorful, upright touch to gardens. It flowers mainly from July to August, reaching heights of 90 to 150 cm (36-60 inches) and spreading over 45 to 60 cm (18-24 inches). The plant’s ease of cultivation, as well as its ability to attract pollinators such as butterflies, makes it an excellent choice for gardens that are sustainable and resilient in the face of climate change.

Quelques variétés recommandées L. spicata ‘Alba’, L. spicata ‘Floristan Violett’, L. spicata ‘Floristan Weiss’, L. spicata ‘Kobold’, L. spicata ‘Kobold Original’.

Coneflower (Rudbeckia)

Black-Eyed Susan, also known as coneflower, is a highly resilient plant native to North America. It is particularly appreciated for its large yellow flowers with a central disc that is often brown or black. There are around 30 species of rudbeckias, all adapted to different climates and soil conditions. They tolerate drought as well as well-drained soils, and some species even prefer wetter soils. Rudbeckies flower for a very long time, usually from July to September, or even October. As well as being decorative, they attract butterflies and granivorous birds, thus contributing to biodiversity.

Maintenance is minimal, requiring only an occasional application of compost and removal of dried stems in spring. Rudbeckias are easily propagated by seed, stem cuttings or division, depending on the species. Their robustness against disease and ability to reseed naturally make them ideal for gardens, flowerbeds and naturalized areas.

Some recommended varieties: R. hirta ‘Indian Summer’, R. hirta ‘Prairie Sun’, R. fulgida sullivantii ‘Early Bird Gold’.

Perennial sunflower (Helianthus)

The Helianthus genus comprises around 150 species, mostly perennials, native to North America. Unlike the annual sunflower, perennial sunflowers have branched stems bearing numerous daisy-like flowers. Adapted to a wide range of hardiness zones (3-5), they are able to survive in a variety of climatic conditions. They prefer full sun, but tolerate part shade and adapt to ordinary, well-drained, slightly moist soils. Although most species prefer moist soil, some, like H. mollis, tolerate drought well. Many helianthus thrive in very wet, even marshy, soils, making them resistant to temporary flooding.

iaTheir stiff, upright stems enable them to withstand wind, and they tolerate the heat of North American prairies well. Adapted to colder hardiness zones, they survive harsh winters. In general, sunflowers are not very susceptible to disease. Although some species can be invasive, many are native and non-invasive. Their flowers attract pollinators and their seeds feed birds. Perennial sunflowers are a resilient and versatile choice for the garden, able to adapt to a variety of conditions while supporting local wildlife.

Some recommended varieties: H. decapetalus, H. x multiflorus ‘Anemoniflorus Flore Pleno’, H. ‘Lemon Queen’.

Goldenrod (Solidago)

The Solidago genus, commonly known as goldenrod, comprises some 125 species, mainly native to North America, with a few also found in Eurasia and South America. These perennials, which vary in size and shape, are often characterized by lanceolate, toothed leaves and yellow flowers in feathery panicles or erect spikes. The name Solidago derives from the Latin solido, meaning “to make strong” or “to heal”, in reference to its historic medicinal properties.

Goldenrod is highly resistant to climate change, thanks to its ability to adapt to a variety of soils and climates. It tolerates drought well once established and can thrive in rich or poor, acid or alkaline soils. Its preference for well-drained soils and a certain tolerance to shade enable it to adapt easily to changing conditions. What’s more, this plant is generally unaffected by deer and tolerates minor diseases with no significant impact on its growth.

Cultivated varieties offer non-spreading clump growth, ideal for sustainable gardens. They attract butterflies and granivorous birds, contributing to local biodiversity while adding beauty to the autumn landscape.

Quelques variétés recommandées: S. rugosa ‘Fireworks’, S. sphacelata ‘Golden Fleece’, S. cutleri ‘Goldrush’, S. flexicaulis ‘Variegata’, S. x ‘Goldenmosa’.