The United Kingdom’s traditionally temperate climate, which has long supported a diverse array of garden plants from around the world, is undergoing significant shifts due to climate change, prompting horticultural adaptation. Increasingly frequent heatwaves, droughts, heavier rainfall in winter, and stronger storms are altering growing conditions, challenging gardeners and plant collections across the country.

In response, the Royal Horticultural Society (RHS) is relocating certain collections—including rhododendrons, gooseberries, and rhubarb—from its Wisley gardens in Surrey to sites in North Yorkshire and Salford. The RHS is also considering moving some hydrangea varieties, which have shown decreased tolerance to rising temperatures and prolonged dry spells.

Historically, garden trends changed primarily with fashion, but current shifts are driven by environmental realities. Temperate plants typically thrive within a 20-30°C summer temperature range, and exposure to higher temperatures can cause stress, leading to premature leaf loss, scorching, or wilting. Supporting plants through short heat episodes may be possible, but sustained watering during extended dry periods is not a viable or sustainable option given water supply constraints.

One challenge is selecting species that can endure both hotter, drier summers and wet, often freezing winters common to much of the UK. Mediterranean plants, which naturally tolerate drought and heat, face difficulties with cold, fluctuating winter conditions and can become vulnerable if grown in nutrient-rich, heavy soils unsuited to their adaptations.

Gardeners are advised to adopt practices that enhance resilience. Raised beds can improve drainage in waterlogged areas, while mulching with compost provides moisture retention and supports fungal networks essential to plant health. Timing of planting is also shifting; autumn is becoming the preferred season for establishing many plants, allowing better root development ahead of summer, although Mediterranean species generally benefit from spring planting and gravel mulches to avoid excess moisture.

Looking ahead, climate models project that by 2050, London's climate will resemble that of Barcelona. This underscores the importance of selecting tree species suited to warmer conditions. Research highlights species such as hornbeam (Carpinus betulus), Judas tree (Cercis siliquastrum), and pride of India (Koelreuteria paniculata) as demonstrably resilient. Stress symptoms like premature leaf drop, sometimes described as a “false autumn,” often indicate environmental mismatch rather than imminent plant death and can be mitigated with improved soil care.

Water conservation is increasingly critical. With hosepipe bans becoming commonplace during summer months, gardeners are encouraged to install rainwater harvesting systems or at least connect water butts to capture runoff from gutters.

Summer perennials, typically vibrant, have been fading earlier than expected this year, a response parallel to Mediterranean plants entering dormancy during extreme heat. Evergreens may gain prominence for providing year-round structure and shade, heralding a shift in aesthetic preferences as gardeners adjust to new climatic realities.

Plant species identified as resilient and adaptable for changing conditions include Stachys byzantina (lamb’s ear), notable for drought and flood tolerance; Verbena bonariensis, valued for its long blooms and appeal to pollinators; and Asplenium scolopendrium (hart’s-tongue fern), which thrives in shaded, dry areas. Succulent varieties like Hylotelephium ‘Matrona’ offer drought resistance, while evergreen climbers such as Trachelospermum jasminoides (star jasmine) can provide shade and ornamental value. Mediterranean natives like Arbutus unedo (strawberry tree) are recommended for well-drained soils.

Other drought-resilient plants include Foeniculum vulgare (fennel), which supports insect life and winter bird feeding; hydrangea ‘Limelight,’ noted for adaptability to sun; and Pinus mugo ‘Mops,’ a low-maintenance pine providing structural greenery. Native species such as Acer campestre (field maple) are also highlighted for their robustness and ecological benefits. For ground cover, Nepeta ‘Walker’s Low’ (catmint) is suggested as a longer-lasting alternative to lavender in damp soils.

As the UK’s climate continues to evolve, gardeners may need to embrace experimentation and flexibility, recognizing that traditional planting choices and garden maintenance routines will require adjustment to ensure healthy, sustainable gardens in the face of changing environmental conditions.