The Missing Genera campaign asks people with a passion for plants to put together a National Plant Collection of their own and join the Plant Heritage community in growing, sharing and saving plants.
Every year we highlight much-loved plant groups that are currently not represented by a National Plant Collection. Thanks to campaigns in recent years we have seen new collections coming through for Eryngium, Alcea, Ginkgo, Achillea and Aeonium.
Though we may choose some each year to highlight, there are actually hundreds of genera of garden plants grown in the UK that don't have collections. So whether you're curious about cacti or crazy for conifers, there will be a plant group to suit your passion.
Top 10 missing genera plants for 2021
Also known as bellflowers, these distinctive open, bell-shaped flowers come in shades blue, pink, purple and white, and range from creeping alpine plants to tall border favourites. There are about 80 species and 232 cultivars currently available but any potential collection could choose to do just a subset of these, for example, just Campanula persicifolia cultivars.
Related to daisies, Erigeron can be annuals, biennials or perennial. They thrive in sunny spots with some happily growing through the cracks in paving. There are 30 cultivars currently available in the UK, with many more to be found worldwide.
From creeping, ground cover plants to stately perennials, this genus can survive in a variety of settings. The UK native species have yellow flowers, but the garden types include whites and deep maroons.
Papaver (Oriental Group)
These pretty perennial poppies are a stalwart of early summer. Since the 19th century oriental poppies have been bred to produce a range of coloured flowers, from pastel shades to deep plums, in addition to their original red.
Also called New Zealand flax, this vigorous, easy to grow plant looks good all year round. Good for windy or coastal sites, the long, strap-like leaves vary from deep purples to reds and yellows, and can also be striped. There are about 60 cultivars available.
These are low growing evergreen shrubs but are often treated as perennials. The tubular flowers are held on long stems and come in stunning tones of pink, red and occasionally yellow, and will last from mid-summer into the autumn.
The glossy, evergreen leaves are the standout feature of these shrubs or small trees, which can be used for hedging, ground cover or as specimen plants. The small flowers can be scented and are produced in late spring to early summer.
These make popular houseplants due to their tolerance for low light. Also known as ‘mother-in-law’s tongues’, the upright, leathery leaves come in many patterns of variegation.
Some Silene are familiar wildflowers, also known as campions or catchflys. There are many other species to be found in the UK, from alpines to border perennials. The colour palette of Silene ranges from pinks, lilacs, whites and reds, and they flower from late spring through early summer. The genus Lychnis is now included in Silene.
Commonly called arum lilies, these hardy, outdoor plant tends to have white flowers and thrive in damp places. There are also more tender forms that come in a range of colours. There are about 70 cultivars available of these dramatic plants in the UK.
As well as the top 10 highlighted above, here are some further ideas of plant groups that aren't currently covered by a National Plant Collection.
Take a look at our Start a National Plant Collection page for details of where to begin.
The full list of genera without a collection can be downloaded from the link below. Be warned - it is very long!
Top 5 missing trees
Prunus armeniaca (Apricot)
Apricots have been grown in the UK since Tudor times and the ‘Moorpark’ cultivar was referenced by Jane Austin in Mansfield Park. There are also many new cultivars being introduced with better cold tolerance or a dwarf habit. There are currently 30 cultivars available for sale in the UK.
Sequoia and Sequoiadendron
There are a handful of each genus in cultivation in the UK. One for those with plenty of space.
Over 50 cultivars of cedars are spread over 4 species. It would be possible to choose just one species to focus on.
Also known as the golden rain tree, there are nine species, subspecies and cultivars currently available.
Deciduous trees with spines and fern-like foliage, and with attractive flowers. Four species and seven cultivars currently available.
Top 5 missing marginals/wet garden plants
The fragrant flowers of meadowsweet grow wild in wet places but there are also many other species (9) and cultivated forms (20) grown in our gardens.
Better known as bulrushes, there are 7 species or cultivars currently available.
The marsh marigolds suit a waterside position. 5 species and 10 cultivars available.
Over 20 cultivars are currently available of this attractive perennial with tall spikes of purple flowers.
There are 13 species and over 30 cultivars of this tall perennial with yellow flowers and striking foliage.
Top 5 missing grasses etc.
There are over 70 ornamental sedge cultivars available in the UK, that come in a range of colours.
This elegant, tufted grass grows in a range of conditions. There are 21 cultivars currently available.
These grasses are often found in shades of glaucous blue, and have fine, needle like leaves. 20 cultivars and over 20 species are currently for sale in the UK.
An unusual member of the sedge family, with clusters of leaves and flowers at the top of the stems. Ten species and a couple of cultivars are currently available in UK horticulture.
The wood-rushes thrive in shady places and have attractive and long lasting flower heads. Around eight species and fifteen cultivars are available.
Top 10 missing shrubs
Berberis come in deciduous or evergreen forms and are known for their colourful flowers and berries, as well as their thorns. The flowers are very attractive to pollinating insects and some have edible berries. The most familiar species is B. thunbergii, with almost 70 cultivars available, but there are also over 30 species grown in the UK.
For delicious scent which fills the air on a still day, Elaeagnus is a winner. The various species flower either in spring and early summer or in the autumn. They are also known for foliage interest and some have edible berries too. There are 45 species and cultivars currently available.
Five species and five cultivars as well as a handful of other forms are currently available of this fragrant, winter flowering genus.
Pieris are grown for both flowers and foliage interest. They need moist, acid conditions and there are 45 cultivars currently available.
There are about 60 cultivars available of this colourful, hardy plant group.
Deciduous shrub with beautiful arching branches of pink or white flowers. 20 species and 50 cultivars currently available.
Evergreen shrubs or trees with small, often fragrant, 5 petalled
flowers, hardy in mild areas. Over 20 species and 66 cultivars available.
Evergreen shrub with attractive foliage. There are 17 cultivars and 10 species in cultivation in the UK.
Also known as broom, this spring/early summer flowering shrub has bright yellow flowers along the long, arching stems. In the UK there are currently 10 species and 8 cultivars available.
This small shrub sports sprays of white flowers, red berries and attractive autumn colour. There are 17 cultivars currently available.
Top 10 missing perennials
Gaura are drought tolerant, deciduous perennials, that flower for a long period at the end of summer and into autumn. There are about 50 cultivars listed in the RHS Plant Finder, largely in shades of pinks and whites. Popular in prairie style planting. Recently reclassified as Oenothera (G)
Also known as monkshood or wolfs-bane, these beautiful border plants belie their poisonous nature. There are about 35 species and 45 cultivars currently available.
Nine species and 7 cultivars make up this pretty genus of low growing perennials, with spikes of white, lilac or magenta flowers.
Tall perennials with airy clusters of tiny flowers, there are over 30 species and about 50 cultivars currently available.
Papaver (Oriental Group)
Perennial oriental poppies are a stalwart of early summer. There are currently about 70 cultivars listed for sale today.
Related to daisies, these plants thrive in a sunny spot and flower over a long period. There are 20 species and 30 cultivars currently available.
From ground creepers to stately perennials, there are about 20 species and 20 cultivars currently available.
These are low growing evergreen shrubs, but often treated as perennials in the garden. The tubular flowers in pinks, reds and occasionally yellow last from mid summer into the autumn. There are 24 cultivars currently available.
There are about 80 species and 232 cultivars currently available but any potential collection could choose to do just a subset of these, for example, just Campanula persicifolia cultivars.
There are about 70 cultivars available of these dramatic plants. The hardy outdoor types tend to have white flowers whilst the indoor ones come in a range of colours.