How to grow geraniums

Choosing the right geranium

• For sunny borders try: G. pratense, G. clarkei, G. psilostemon, G. himalayense, G. renardii
• For shaded spots try: G. phaeum, G. maccrorrhizum, G.sylvaticum, G. endressii
• For rock gardens and alpine containers try: G. argenteum, G. cinereum, G. dalmaticum 

Tender geraniums

• For exotic gardens, cool greenhouses, conservatories and pots try: G. maderense, G. palmatum

Buying geraniums

• You will normally find hardy geraniums for sale in garden centres and a wider selection at specialist nurseries and by mail order/online. You can buy young and more established geraniums in containers – 9cm (3½in) or larger – ready for planting out
• Some nurseries may offer
  These have been lifted from the ground while dormant, with little or no soil around their roots. Various plants may be available bare root, including fruit trees, hedging plants and some perennials. They are generally cheaper than plants in containers, but are only available in winter/early spring, while dormant

  bare-root plants during the winter
  Dormancy refers to a period of inactivity in plants, during which they slow down or stop their growth, conserving energy and resources. This is a natural process that helps them survive harsh conditions, such as winter or drought. Dormancy in seeds is a mechanism that prevents them germinating until environmental conditions are favourable for growth.

  dormant season
• You can grow species from seed, for example the hardy G. endressii, G. pratense and G. nodosum or two non-hardy species, G. maderense and G. palmatum

When to plant geraniums

• Container-grown hardy geraniums can be planted at any time if soil is not waterlogged, but will establish more quickly if planted in spring 
• On heavy soil, early spring planting is best as plants may rot over winter after autumn planting
• If planting container-grown plants in summer, keep the soil moist until they establish
• Plant
  These have been lifted from the ground while dormant, with little or no soil around their roots. Various plants may be available bare root, including fruit trees, hedging plants and some perennials. They are generally cheaper than plants in containers, but are only available in winter/early spring, while dormant

  bare-root plants on arrival or pot up and grow on

Where to plant geraniums

• Hardy geraniums enjoy most garden soils so long as it isn’t
  Describes soil or potting compost that is saturated with water. The water displaces air from the spaces between soil particles and plant roots can literally drown, unless they are adapted to growing in waterlogged conditions. Waterlogging is common on poorly drained soil or when heavy soil is compacted. 

  waterlogged in winter
• Check if the
  Gardeners often use the word variety when referring to a specific plant, but the correct botanical term is 'cultivar'. Whichever word you use, it means a distinctive plant or plants, given a specific cultivar name and usually bred to enhance certain characteristics, such as flower or fruit size, colour, flavour or fragrance, plant size, hardiness, disease resistance, etc. Additionally, it is worth knowing that, botanically, variety has another meaning - it refers to a naturally-occurring distinct plant that only has slight differences in its looks. For example, Malva alcea var. fastigiata differs from typical plants by having an upright habit.

  cultivar you have can thrive in shade; some geraniums prefer a sunny place
• The small, often silver-leaved types prefer the sharp drainage of a rock garden or alpine container in full sun
• For tender geraniums, find a sheltered site in full sun if you live in a milder area. Alternatively grow them in a big pot so you can bring them into a frost-free greenhouse or conservatory in winter

How to plant geraniums

• Hardy geraniums are easy to plant, just like other herbaceous perennials
• Treat small cultivars as you would alpines in troughs
• Plant up the tender species in containers or as herbaceous
  Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs.

  perennials if you’re growing them outside. For container growing, select a sturdy pot and
  Can refer to either home-made garden compost or seed/potting compost: • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

  compost such as peat-free John Innes No. 2 to help prevent large plants blowing over
• To check the planting distance refer to the plant label for final width

Watering geraniums

• Water new plants as the weather warms up in spring, until they establish through their first spring and summer 

Feeding geraniums

• Feeding is not generally necessary on most garden soils, but you can apply a fertiliser if plants are showing a nutrient deficiency

• Liquid feed container-grown tender species (G. maderense and G. palmatum) with a general fertiliser such as a seaweed-based product from spring to late summer

Weeding

• Keep beds free from weeds. A 5cm (2in) thick layer of
  Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings.

  mulch with well-rotted organic matter such as homemade compost or bagged manure will help here

Deadheading

• Deadheading isn’t normally required in hardy geraniums. Instead, look to a mid season cut back, sometimes known as the Hampton hack. (See ‘Pruning and training’ below)
• Deadhead tender species to prolong flowering unless you want to save seed

Rejuvenation

• Species that create good groundcover, for example G. macrorrhizum, will need keeping in check by occasional division in autumn or spring
• ​Clump-forming cultivars can benefit from dividing to rejuvenate every few years, but generally, hardy geraniums are long-lived

Additional care tips for tender geraniums

• For growing G. maderense and G. palmatum outside, in spring, pot up young plants raised from seed and those that have self-seeded, into their large summer containers. Alternatively, plant out in sheltered, sunny borders

Cutting back geraniums

• For most hardy border geraniums that flower in summer, cut plants back to ground level after the flowering stems have finished, often in June or July (known as the Hampton hack). This will encourage fresh foliage and maybe more flowers. In dry weather, water these clumps to promote new leaves
• For spring-flowering species such as G. malviflorum that are
  Dormancy refers to a period of inactivity in plants, during which they slow down or stop their growth, conserving energy and resources. This is a natural process that helps them survive harsh conditions, such as winter or drought. Dormancy in seeds is a mechanism that prevents them germinating until environmental conditions are favourable for growth.

  dormant (die down) in summer, you may want to tidy away old foliage, as fresh growth will appear in autumn
• In autumn, most hardy geranium foliage in beds or alpine troughs will die down for winter. This can be tidied away ready for spring regrowth
• Don’t cut back foliage from tender geraniums on plants that have not yet flowered. Instead, overwinter the
  Rosettes are the circular arrangement of flower petals; or a cluster of leaves radiating from approximately the same point usually around a stem. Examples include aeonium and most succulent plants, African violets, primula, sempervivums.

  rosettes of leaves

• For clump formers and creepers (the vast majority of hardy geraniums), division in spring is easiest. Replant smaller sections or
  Rhizomes are creeping swollen root-like structures that are actually adapted stems. Roots, stems with leaves and flowers are produced along its length. See plants such as Anemone nemorosa, bamboo, canna, border iris.

  rhizomes or pot these up and grow on. Those with compact rootstocks may need a knife to divide the growing points, for example G. pratense
• For tuberous species, pot up small tubers in their
  Dormancy refers to a period of inactivity in plants, during which they slow down or stop their growth, conserving energy and resources. This is a natural process that helps them survive harsh conditions, such as winter or drought. Dormancy in seeds is a mechanism that prevents them germinating until environmental conditions are favourable for growth.

  dormant season to grow on, for example G. malviflorum and G. tuberosum

• Stem cuttings: try for G. ‘Anne Folkard’ or G. wallichianum ‘Buxton’s Variety’
• Rhizome cuttings: try for G. sanguineum or G. × cantabrigiense
• Seed: sow species seed in spring. (Remember though that seed saved from cultivars won’t come true to type)

• Save seed and sow in spring,
  Transferring young plants from one container to a slightly larger one, where they will have more room to grow and fresh potting compost. This encourages continuous, healthy growth.

  growing on in frost-free conditions. Then plant out the young plants into pots or a greenhouse border the following spring. In mild locations, they'll thrive in a sunny sheltered spot
• G. maderense may make small offshoots on its woody stem. These can be grown on as cuttings

• Geraniums are generally robust and trouble-free
• In dry conditions they may be affected by powdery mildew
• In containers, they may be affected by vine weevil damage
• Tender species may be affected by cold winds and frost damage if not protected or overwintered in a frost-free place