What to Plant in September
Seeds to sow, young plants to put out, and what's flowering in September in UK gardens — drawn straight from the GardenWizz plant encyclopedia.
🌱 Sow in September
Sow these seeds this month (38 plants).
Apple (Malus domestica)
Autumn Sage (Salvia greggii)
Bearberry (Arctostaphylos uva-ursi)
Bukhara Iris (Iris bucharica)
Bulb Onion (Allium cepa)
Chamomile (Matricaria chamomilla)
Common Bent (Agrostis capillaris)
Common Dog-Violet (Viola riviniana)
Common Teasel (Dipsacus fullonum)
Cornflower (Centaurea cyanus)
Cowslip (Primula veris)
Crab Apple (Malus sylvestris)
Daffodils (Narcissus)
Fern (Dryopteris filix-mas)
Field Maple (Acer campestre)
Guelder Rose (Viburnum opulus)
Highbush Blueberry (Vaccinium corymbosum)
Holly (Ilex aquifolium)
Japanese Maple (Acer palmatum)
Long-Scape Iris (Iris delavayi)
Lupin (Lupinus)
Michaelmas Daisy (Symphyotrichum novi-belgii)
Orchid Iris (Iris histrioides)
Pink Lily Leek (Allium oreophilum)
Poppy (Papaver)
Potato (Solanum tuberosum)
Pot Marigold (Calendula officinalis)
Raspberry (Rubus idaeus)
Red Bartsia (Odontites vernus)
Red Campion (Silene dioica)
Red Clover (Trifolium pratense)
Small Yellow Onion (Allium flavum)
Snapdragon (Antirrhinum majus)
Strawberry (Fragaria × ananassa)
Sweet Pea (Lathyrus odoratus)
Tulip (Tulipa)
Wayfaring Tree (Viburnum lantana)
Whitebeam (Sorbus aria)
🪴 Plant out in September
Put these into the garden now (174 plants).
Allium (Allium hollandicum)
Aloe
Altai Tulip (Tulipa altaica)
Apothecary's Rose (Rosa gallica)
Aspen (Populus tremula)
Avens (Geum)
Azalea (Rhododendron)
Bamboo Iris (Iris confusa)
Barberry (Berberis)
Bay Tree (Laurus nobilis)
Bearded Iris (Iris germanica)
Bear's Breech (Acanthus mollis)
Bear's Ear (Primula auricula)
Bell Heather (Erica cinerea)
Big-Leaf Rhododendron (Rhododendron calophytum)
Birch-Leaved Bellflower (Campanula betulifolia)
Blackberry (Rubus fruticosus)
Blood Iris (Iris sanguinea)
Blue Allium (Allium cyaneum)
Bluebell (Hyacinthoides non-scripta)
Blue Garlic (Allium caesium)
Boxwood (Buxus sempervirens)
Bristle-Pointed Iris (Iris setosa)
Bugle (Ajuga reptans)
Bukhara Iris (Iris bucharica)
Bulb Onion (Allium cepa)
Bulley's Primrose (Primula bulleyana)
Buttonhead Primrose (Primula capitata)
Byzantine Crocus (Crocus banaticus)
Cape Cowslip (Lachenalia)
Catalonian Jasmine (Jasminum grandiflorum)
Catmint (Nepeta)
Chamomile (Matricaria chamomilla)
Chicory (Cichorium intybus)
Chinese Wisteria (Wisteria sinensis)
Common Bent (Agrostis capillaris)
Common Bird's-Foot-Trefoil (Lotus corniculatus)
Common Camellia (Camellia japonica)
Common Dog-Violet (Viola riviniana)
Common Lilac (Syringa vulgaris)
Common Mint (Mentha spicata)
Common Sorrel (Rumex acetosa)
Copper Iris (Iris fulva)
Coral Bells (Heuchera)
Cow Parsley (Anthriscus sylvestris)
Cowslip (Primula veris)
Crimean Iris (Iris lutescens)
Crocus (Crocus vernus)
Daffodils (Narcissus)
Dalmatian Cranesbill (Geranium dalmaticum)
Daphne Rhododendron (Rhododendron campylogynum)
Daurian Rhododendron (Rhododendron dauricum)
Davidson's Rhododendron (Rhododendron davidsonianum)
Daylily (Hemerocallis)
Dogwood (Cornus)
Dogwood (Cornus sanguinea)
Druce's Cranesbill (Geranium × oxonianum)
Dryopteris affinis
Early Azalea (Rhododendron lutescens)
Edgeworth's Rhododendron (Rhododendron edgeworthii)
Elder (Sambucus nigra)
English Ivy (Hedera helix)
English Lavender (Lavandula angustifolia)
European Larch (Larix decidua)
Fern (Dryopteris filix-mas)
Field Birch (Betula pubescens)
Florentine Iris (Iris florentina)
Fortune's Rhododendron (Rhododendron fortunei)
Foxglove (Digitalis purpurea)
Fulvous Rhododendron (Rhododendron fulvum)
Garden Phlox (Phlox arendsii)
Gorse (Ulex europaeus)
Grass-Leaved Flag (Iris graminea)
Great White Rhododendron (Rhododendron decorum)
Hairyflower Bellflower (Campanula chamissonis)
Hairy Grey Heather (Erica canaliculata)
Hance's Rhododendron (Rhododendron hanceanum)
Heather (Calluna vulgaris)
Hellebore (Helleborus)
Hollyhock (Alcea rosea)
Hornbeam (Carpinus betulus)
Hypericum Dummeri (Hypericum × dummeri)
Irises (Iris)
Japanese Barberry (Berberis thunbergii)
Japanese Primrose (Primula japonica)
Japanese Spiraea (Spiraea japonica)
Keisk's Rhododendron (Rhododendron keiskei)
Kerner Iris (Iris kerneriana)
Kew Primrose (Primula kewensis)
King Rhododendron (Rhododendron rex)
Korean Rhododendron (Rhododendron mucronulatum)
Kotschy's Crocus (Crocus kotschyanus)
Lachenalia corymbosa
Large Speedwell (Veronica austriaca)
Larkspurs (Delphinium)
Lazistan Iris (Iris lazica)
Leek (Allium porrum)
Lemon Balm (Melissa officinalis)
Lily Of The Valley (Convallaria majalis)
Long-Scape Iris (Iris delavayi)
Magnificent Iris (Iris magnifica)
Magnolia denudata (QA: Magnolia denudata)
Makino's Rhododendron (Rhododendron makinoi)
Many-Branched Rhododendron (Rhododendron polycladum)
Mexican Feather Grass (Stipa tenuissima)
Michaelmas Daisy (Symphyotrichum novi-belgii)
Mint (Mentha)
Moth Orchid 'Ariadne' (Phalaenopsis × ariadne)
Mountain-Loving Rhododendron (Rhododendron oreotrephes)
Nakahara's Rhododendron (Rhododendron nakaharae)
Narrow-Leaved Crocus (Crocus angustifolius)
New England Aster (Symphyotrichum novae-angliae)
Nordmann Fir (Abies nordmanniana)
Notable Rhododendron (Rhododendron insigne)
Ochre Rhododendron (Rhododendron ochraceum)
Orchid Iris (Iris histrioides)
Oven Wattle (Acacia pravissima)
Panicle Hydrangea (Hydrangea paniculata)
Paperbark Maple (Acer griseum)
Persian Onion (Allium jesdianum)
Pink Lily Leek (Allium insubricum)
Pink Lily Leek (Allium oreophilum)
Plantain Lily (Hosta)
Polyanthus Primrose (Primula danova)
Pontic Rhododendron (Rhododendron ponticum)
Primrose-Flowered Rhododendron (Rhododendron primuliflorum)
Primrose (Primula vulgaris)
Primroses (Primula)
Racemose Rhododendron (Rhododendron racemosum)
Red-Barked Dogwood (Cornus alba)
Red Bartsia (Odontites vernus)
Red Campion (Silene dioica)
Red Clover (Trifolium pratense)
Red Currant (Ribes rubrum)
Rosebay Willowherb (Epilobium angustifolium)
Rosemary (Salvia rosmarinus)
Rosy Rhododendron (Rhododendron oreodoxa)
Round-Leaved Rhododendron (Rhododendron orbiculare)
Roxie's Rhododendron (Rhododendron roxieanum)
Shrubby Rock-Roses (Cistus)
Silver-Leaved Rhododendron (Rhododendron argyrophyllum)
Small Yellow Onion (Allium flavum)
Smooth Azalea (Rhododendron arborescens)
Smooth Crocus (Crocus laevigatus)
Snowdrop (Galanthus nivalis)
Snowy Rhododendron (Rhododendron niveum)
Spanish Heath (Erica australis)
Speedwells (Veronica)
Stinking Iris (Iris foetidissima)
St John's Wort (Hypericum perforatum)
Sycamore (Acer pseudoplatanus)
Thick-Flowered Rhododendron (Rhododendron pachysanthum)
Traveller's Joy (Clematis vitalba)
Tree Rhododendron (Rhododendron arboreum)
Tulip (Tulipa)
Upright Rhododendron (Rhododendron fastigiatum)
Viburnums (Viburnum)
Wall Speedwell (Veronica albicans)
Water Iris (Iris laevigata)
Weigela (Weigela florida)
White Clover (Trifolium repens)
White Dead-Nettle (Lamium album)
Wild Garlic (Allium ursinum)
Wild Geranium (Geranium maculatum)
Wild Mint (Mentha arvensis)
Wild Strawberry (Fragaria vesca)
Winter Heath (Erica carnea)
Wood Anemone (Anemonoides nemorosa)
Woodrush (Luzula sylvatica)
Wood Sorrel (Oxalis acetosella)
Yellow Crocus (Crocus flavus)
Yellow Crocus Iris (Iris crocea)
Yunnan Iris (Iris forrestii)
ZZ Plant (Zamioculcas zamiifolia)
🌸 In flower in September
What's blooming this month (98 plants).
Aloe
Anise-Scented Sage (Salvia guaranitica)
Autumn Crocus (Colchicum autumnale)
Autumn Sage (Salvia greggii)
Beardtongue (Penstemon)
Bedding Pelargonium (Pelargonium × hortorum)
Begonias (Begonia)
Bellflowers (Campanula)
Bigleaf Hydrangea (Hydrangea macrophylla)
Bigleaf Hydrangea (Hydrangea macrophylla)
Blue Allium (Allium cyaneum)
Borage (Borago officinalis)
Brilliant Fuchsia (Fuchsia fulgens)
Bromfield's Living Stone (Lithops bromfieldii)
Bulb Onion (Allium cepa)
Buttonhead Primrose (Primula capitata)
Byzantine Crocus (Crocus banaticus)
Cape Cowslip (Lachenalia)
Cardinal Sage (Salvia fulgens)
Carrot (Daucus carota subsp. sativus)
Catalonian Jasmine (Jasminum grandiflorum)
Catmint (Nepeta)
Chamomile (Matricaria chamomilla)
Chenille Plant (Acalypha hispida)
Chicory (Cichorium intybus)
Chrysanthemum (Chrysanthemum morifolium)
Clustered Bellflower (Campanula glomerata)
Common Bird's-Foot-Trefoil (Lotus corniculatus)
Common Daisy (Bellis perennis)
Common Mint (Mentha spicata)
Coneflower (Echinacea purpurea)
Coral Bells (Heuchera)
Cornflower (Centaurea cyanus)
Corrugated Sage (Salvia corrugata)
Crocosmia (Crocosmia crocosmiiflora)
Druce's Cranesbill (Geranium × oxonianum)
English Ivy (Hedera helix)
Etruscan Honeysuckle (Lonicera etrusca)
Fall Crocus (Crocus goulimyi)
Fern-Leaved Begonia (Begonia foliosa)
Fire Heath (Erica cerinthoides)
Foxglove (Digitalis purpurea)
Fuchsias (Fuchsia)
Garden Cosmos (Cosmos bipinnatus)
Garden Dahlia (Dahlia pinnata)
Garden Parsley (Petroselinum crispum)
Garden Phlox (Phlox arendsii)
Hardy Begonia (Begonia grandis)
Heather (Calluna vulgaris)
Hollyhock (Alcea rosea)
Honeysuckle (Lonicera periclymenum)
Horned Spurge (Euphorbia ceratocarpa)
Jame Sage (Salvia × jamensis)
Kotschy's Crocus (Crocus kotschyanus)
Lady's Eardrops (Fuchsia boliviana)
Large Speedwell (Veronica austriaca)
Lithops dorotheae
Maple Leaf Begonia (Begonia dregei)
Marigolds (Tagetes)
Mexican-Giant (Echeveria colorata)
Michaelmas Daisy (Symphyotrichum novi-belgii)
Moth Orchid 'Ariadne' (Phalaenopsis × ariadne)
Moth Orchid (Phalaenopsis)
Nasturtium (Tropaeolum majus)
New England Aster (Symphyotrichum novae-angliae)
Panicle Hydrangea (Hydrangea paniculata)
Peace Lily (Spathiphyllum wallisii)
Petunia (Petunia x hybrida)
Pot Marigold (Calendula officinalis)
Primroses (Primula)
Red Bartsia (Odontites vernus)
Red Campion (Silene dioica)
Rosebay Willowherb (Epilobium angustifolium)
Roseleaf Sage (Salvia involucrata)
Rudbeckia (Rudbeckia fulgida)
Runner Bean (Phaseolus coccineus)
Russian Sage (Perovskia atriplicifolia)
Sabra Spike Sage (Salvia confertiflora)
Sea Milkball (Euphorbia flanaganii)
Silver Wattle (Acacia dealbata)
Smooth Azalea (Rhododendron arborescens)
Smooth Crocus (Crocus laevigatus)
Snapdragon (Antirrhinum majus)
Spider Plant (Chlorophytum comosum)
St. John's Worts (Hypericum)
Stonecrop (Sedum)
Strawberry Tree (Arbutus unedo)
Thread Agave (Agave filifera)
Traveller's Joy (Clematis vitalba)
Tree Fuchsia (Fuchsia arborescens)
Tropical Sage (Salvia coccinea)
Twin-Spined Cactus (Mammillaria geminispina)
Two-Lobed Cone Plant (Conophytum bilobum)
Verbena (Verbena bonariensis)
White Dead-Nettle (Lamium album)
Wild Saffron (Crocus cartwrightianus)
Yarrow (Achillea millefolium)
ZZ Plant (Zamioculcas zamiifolia)
❄️ UK frost dates by region
Approximate last spring / first autumn frost — always check your local forecast before sowing or planting out tender plants.
| Region | Last spring frost | First autumn frost |
|---|---|---|
| Scotland & far north | late May | late September |
| North of England | mid May | mid October |
| Midlands & Wales | early–mid May | late October |
| East & South East England | late April–early May | late October |
| London & urban areas | mid April | early November |
| South West & coastal | mid April | November |
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