Exotic and subtropical gardening

Create the atmosphere of a lush subtropical oasis in your own garden using bold foliage and dazzling hot flower colours.

Wisley Exotic Garden

Wisley Exotic Garden

Quick facts

Suitable for: warm protected gardens
Timing: spring propagation and planting out when frosts are over, summer planting and maintenance, autumn preparation for winter, overwintering tender plants
Difficulty: moderate to difficult; half hardy and tender plants need winter protection and care

What is an exotic-style garden?

Unlike a typical English garden, an exotic-style garden doesn't have all-year-round interest, instead peaking in a mass of vegetation in summer. However, careful plant choice can extend the season a little into winter.

The typical characteristics of a subtropical garden scheme are exuberant plant with large leaves, structural forms and striking flower colours. This can be achieved in most garden situations providing the necessary conditions are met (see below).

Choosing suitable exotic-style plants

Some design and planting considerations:

  • Add depth with a mix of leaf shapes and colours combining hardy and half hardy subjects, for example graceful palms and lacy tree ferns, bananas with long paddle-shaped leaves and canna such as C. 'Phasion' with striking foliage colours
  • Use architectural silvery Astelia chathamica AGM, cordyline and Phormium tenax as permanent structural planting; these plants are valuable for winter interest
  • Try grouping tender indoor plants such as begonia and hibiscus with more familiar outdoor dahlia, fuchsia, gladiolus and lobelia to create further design and colour possibilities
  • Choose showy but hardy agapanthus, bamboo, jasmine, honeysuckle and hardy hibiscus cultivars including H. syriacus 'Hamabo' AGM for an exotic feel without the need for winter care
  • Pollarding hardy plants Catalpa bignonioides 'Aurea' AGM, Paulownia tomentosa AGM and
    Cotinus 'Grace' for large, bold or colourful leaves (but at the expense of flowers) can also give an exotic feel without winter protection
  • Low-growing, shade-loving hardy ferns and hosta cultivars make excellent groundcover as they can form wide-spreading mounds of foliage
  • If space is an issue or when just a taste of the tropics is needed, plant up containers to display in a courtyard or patio. With correct maintenance to ensure they are not frozen in winter or dried out and overheated in summer, they will thrive and can easily be moved inside if necessary

See Exotic and subtropical plants for a widely available range of suitable hardy and tender plants. Many of the cultivars listed have received the RHS Award of Garden Merit (AGM) and can be sourced through the RHS Find a Plant.

How to establish exotic-style planting

Exotic-style gardens can be made up of many plants with different care needs. The proportion of each depends on the available overwintering facilities and the time required for propagating plants and planting out each year.

Pick and mix your scheme from the following plant types;

  1. Permanently planted hardy plants that can be left outside during winter. These shrubs, especially evergreens, are useful for providing a framework, creating windbreaks and micro-climates even in cold gardens, for example evergreen shrubs Daphniphyllum macropodum and Tetrapanax papyrifer 'Rex'.
  2. Permanently planted shrubs but needing winter protection with a dry mulch or fleece include tree ferns, bananas and palms.
  3. Tender perennials needing dry winter storage in a frost-free greenhouse or shed include dahlia tubers.
  4. Tender shrubs and container plants needing a conservatory or heated greenhouse, for example succulents including Aeonium 'Zwartkop', echeveria and kalanchoe.

How to care for plants through the seasons

Follow this seasonal care plan to help make your exotic-style garden a success.

Spring

Plants under cover (greenhouse or conservatory)

Outdoors

  • Sow hardy annuals in situ
  • Pot on any container plants needing more space
  • Plant out all summer-flowering bulbs such as gladioli and cardiocrinum
  • Harden off plants needing acclimatising to outdoor conditions on warm days and increase greenhouse ventilation
  • Provide fleecing for vulnerable plants that are putting on soft growth and prune out any frost damaged growth
  • Provide slug protection for fresh young growth
  • Divide hardy perennials if overgrown
  • Mulch around plants in situ with well-rotted organic matter such as manure or garden compost
  • Remove winter wrapping from frost hardy permanent plantings for example tree ferns, bananas and palms when when the risk of hard frosts is over

Summer

Regular watering is vital for outdoor plants during dry spells, greenhouse and conservatory plants, and watch out for slugs and snails attacking fresh young growth.

  • Plant out half hardy annuals, summer bedding plants and tender perennials such as pelargonium
  • Plant out annual climbers and put in place frames or wires for climbing
  • Plant out canna, begonia and any potted bulbs including lilies and cardiocrinum started into growth indoors
  • Move container conservatory plants or those stored in the greenhouse and houseplants to be used in exotic-style displays outside in June but provide shade for soft leaves vulnerable to scorching in strong sunshine
  • Feed plants monthly with a fertiliser such as Vitax Q4
  • Deadhead flowers to promote further flowering
  • Take softwood cuttings of pelargonium in August, choosing non-flowering shoots
  • Damp down the greenhouse, ventilate well and use shading if any plants remain in greenhouse

Autumn

Outdoors most plants are still looking good at this time with lush foliage and plenty of flower but some plants may begin to fade so tidy and remove any dead or dying leaves and flowers.

  • Take more care with watering, days are shorter and it will be cooler
  • Make sure container plants, especially those with succulents are not overwatered
  • Make sure the greenhouse heater is in working order, it may be needed soon for frost-tender plants
  • Bring container conservatory plants, those for greenhouse storage and houseplants used in summer exotic-style planting, under cover towards the end of September
  • Insulate containers with bubble wrap or hessian that are too large to take under cover
  • Tender tubers such as canna and begonia should be lifted and brought inside for storage before any autumn frosts; dahlia tubers can be lifted after first frosts blacken foliage
  • Prepare permanently planted shrubs needing winter protection such a tree ferns, bananas and palms for a straw or bracken mulch to protect vulnerable roots and borderline hardy perennials including salvia to protect crowns
  • Put in place fleece or covers and wrap vulnerable permanent planting of tree ferns, bananas and palms

Winter

Plants under cover (greenhouse and conservatory)

  • Protect seedlings of hardy annuals sown in autumn
  • Tidy plants in the greenhouse and conservatory regularly to help avoid fungal diseases
  • Water plants sparingly and with care, in the morning to allow drying out before cold nights set in
  • Prune tender perennials such as pelargonium, fuschia and salvia that have overwintered
  • Watch out for vine weevil damage especially in pots of fuchsia and begonia
  • Check temperatures in greenhouse and conservatory to keep tender plants frost free and warm
  • Keep greenhouse glass clean and check insulation is gap-free
  • Check bulbs and tubers in storage and remove any showing signs of disease or rotting

Outdoors

  • Check permanent planting in containers for debris and fallen leaves and clean out to avoid fungal problems and overwintering pests
  • Check all container plants, especially evergreens, for water
  • Check fleece and other coverings for permanent planting including tree ferns, bananas and palms to make sure they are secure and in place

Further information

Places to visit

Abbotsbury Subtropical Gardens, Dorset
Great Dixter House and Gardens, East Sussex, Exotic Garden
Royal Botanical Gardens Kew, Palm House
The Minack Theatre, Porthcurno, Cornwall, The Minack Gardens
Tresco Abbey Gardens, Isle of Scilly

RHS Garden, Wisley, Surrey, The Exotic Garden

Books

Exotic Planting for Adventurous Gardeners by C. Lloyd and friends (BBC Books, ISBN 9780563493198)
Encyclopedia of Exotic Plants for Temperate Climates by Will Giles (Timber Press, ISBN 0881927856)
Exotic Gardening by Ian Cooke (Crowood Press, ISBN 9781847972132)
Tropical Garden Style with Hardy Plants by Alan Hemsley (Guild of Master Craftsman Publications, ISBN 1861082371)
Exotic Gardening in Cool Climates by Miles Challis (Fourth Estate, ISBN 1857021878)
The Flower-Powered Garden by Andy Vernon (Timber Press ISBN 978-1604696660)

These books are made available through RHS Libraries.


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