Are you a garden hygienist?
In my experience, most gardeners
fall into two camps when it comes to autumn tidiness: complete clear-out
merchants that leave nothing out of place; or the more relaxed,
let-it-all-rot-down-naturally brigade. Me? I fall somewhere in the
middle. I’ll tidy if there’s a good reason for it, but leave well alone
if it’s just offending my natural sense of order. Take the herbaceous
border, for example. It’s still full of colour from the asters and
sedums, rudbeckias and heleniums, but most of the other early flowering
plants are past their best and could be cleared away. But take a closer
look. See how seemingly dead silhouettes take on a new lease of life in
the watery light on early October mornings as the mists start to clear,
or when bathed in the honey-glow of a fine autumn evening. Bear in mind
they’ll look even more dramatic after a hoar frost in the depths of
winter. Watch and listen, too, how the plumes of ornamental grasses and
other airy seedheads rustle and move in sussurating synchronicity as
they trace the progress of every breeze.
Then
consider whether the fallen foliage could be serving another useful
purpose. If a perennial is only borderline hardy for your garden, for
example, you might be better off leaving the foliage intact to help
provide winter protection. Fallen leaves and stems also offer a winter
refuge for many types of garden wildlife, while seedheads offer food for
the birds and other creatures throughout the winter months. Bear these
things in mind too before you consign it all to the compost heap.
Some herbaceous perennial
plants will be looking the worse for wear because they have been
attacked by a pest or disease, such as powdery mildew or the
ever-present slugs and snails…they’re out in force after the wet summer
in my borders, but where plants look good in their fading days I leave
them to age gracefully. Where this is not the case, clear affected
leaves and any pests you come across to help reduce the carry-over of
the problem next year.
Dealing with grasses
To make the most of ornamental
grasses, you need to tidy them at least once a year. This is a simple
task, but one often overlooked. I think it’s partly because they are
otherwise such undemanding plants, but also because grasses are looking
their best in autumn. They get forgotten until mid-spring when the new
growth is showing, making it too fiddly to cut back. Ornamental grasses,
such as Festuca and Carex need next to no attention –
simply comb through the foliage with your fingers during late winter or
early spring to remove dead foliage and seedheads. However, if you want
to stimulate new growth and better leaf colour, you can cut them back in
early spring. Other grasses, such as
Deschampsia, Stipa, Pennisetum and
Miscanthus should be cut back in late winter, removing last year’s
stems and dead leaves before the new foliage appears. Taller varieties
of Molinia tend to collapse in late autumn and so are worth
tidying before Christmas, though smaller varieties, such as the
variegated Molinia caerulea subsp. caerulea ‘Variegata', often
remain upright throughout the winter and can be cut back before the new
growth appears in spring. A few grasses can self seed prolifically. In
my garden pheasant-tail grass likes to scatter itself around, but I find
a thick mulch makes it easy enough to weed out the seedlings in spring.
Vigorous grasses can spread rapidly by underground runners and so it’s
worth checking at least once a year and severing any runners with a
sharp spade to restrict their spread.
My A-Z checklist for choppers
Acaena Trim
fading flower heads in late October, but leave the evergreen foliage to
provide winter interest.
Acanthus Cut
seedheads back in December, but leave evergreen foliage to provide
winter protection. Tidy foliage in March.
Achillea Cut down
flowering stems to near ground level in November. Tidy foliage in March.
Aconitum Cut down
flowering stems to within 15cm of ground level in November. Always wear
gloves since all parts of the plant are poisonous and a potential skin
irritant.
Acorus If not
already done, cut back faded flower stems to near ground level in
October.
Actaea Leave
flowering stems for winter interest, then remove to near ground level
when the berries have fallen or been eaten, usually December. New plants
should be cut back in November to prevent wind-rock.
Adiantum Cut back
tatty fronds to near ground level in March.
Agapanthus Leave
foliage and use as winter wrapping to protect the crown from frost
between October and April. In colder areas, insulate the crown with a
layer of dry leaves or chipped bark.
Agastache
Leave flowering stems for
winter interest, then remove to near ground level in March.
Ajuga Trim off damaged leaves in March. Use a sharp
spade to cut around the plant and restrict its spread. This will prevent
the center of the plant dying out too.
Alcea Remove and
burn rust-infected plants, replace with new in the spring. Trim healthy
plants to within 15cm of ground level in October to prevent wind-rock in
winter.
Alchemilla
Prevent self-seeding by removing seedheads as they fade. Cut foliage
back to within 3cm of ground level during November.
Alstroemeria Cut
back to about 20cm of ground level in October and insulate the crown
with a layer of dry leaves or chipped bark.
Amsonia Cut right
back to near ground level in November.
Anaphalis Cut
foliage right back to near ground level during November and insulate the
crown with a layer of dry leaves or chipped bark.
Anchusa Cut back
old flowering stems to near ground level during October.
Anemone Remove
and burn disease-infected plants. Remove dead flower stems from healthy
plants in November, cutting them back to near ground level.
Anthemis Cut back
old stems by half during October, but in cold gardens leave foliage to
provide winter protection. Then cut back to within 15cm of ground level
in March.
Anthericum Cut
back stems to near ground level after flowering.
Aquilegia If not
already done, cut border species right back to near ground level in
October, but take care not to damage the new shoots. Alpine species need
deadheading only.
Arabis If not
already done, cut back faded flower stems in October. Remove reverted
green shoots from variegated varieties.
Armeria Trim off
faded flower stems but leave evergreen foliage.
Artemisia Cut
herbaceous species to within 3cm of ground level during October. Leave
the variety ‘Powis Castle’ until March.
Aruncus Cut back
stems to near ground level during October.
Asphodeline Leave
flowering stems for winter interest, then remove to near ground level in
February.
Asplenium Cut
back tatty fronds to ground level in March.
Aster Cut back
fading flower stems to about 15cm of ground level during November.
Astilbe Leave
flowering stems for winter interest, then remove in February.
Astrantia Cut
back faded flower stems to near ground level during November.
Ballota Cut back
flower stems in December, but leave foliage to provide winter
protection.
Baptisia Cut back
faded flower stems to about 15cm of the ground during October.
Bellis Deadhead
regularly to prevent self-seeding and remove tatty foliage in March.
Bergenia Cut back
faded flower stems to near ground level and remove damaged leaves during
November.
Blechnum Cut back
tatty fronds to ground level in March.
Brunnera Cut back
faded flower stems during October. Remove reverted green shoots from
variegated varieties.
Caltha Remove
damaged leaves during October and again in March.
Campanula If not
already done, cut back flowering stems to near ground level in October.
Trim leaves from perennial species in November. Remove and burn
rust-infected plants.
Carex Comb
through the plant during March to remove dead foliage.
Catananche Trim
off faded flower stems to about 15cm during October.
Centaurea Cut
back flower stems to near ground level in November, but leave foliage
until March.
Centranthus Cut
back faded flower stems during October, earlier if self-seeding is a
problem. Tidy foliage in March.
Chelone
Cut back stems to 15cm
during October.
Chrysanthemum Cut
back faded flower stems of hardy types to about 15cm during November,
but leave foliage until March.
Cimicifuga Cut
back flowering stems to near ground level during November. Tidy foliage
in March.
Cirsium Trim off
faded flower stems to near ground level during October, earlier if
self-seeding is a problem. Tidy foliage in February.
Clematis
(herbaceous) Cut back all herbaceous species to near ground level in
March, except C. recta and C. heracleifolia which should
be cut back to a pair of healthy buds about 15cm from the ground.
Codonopsis Cut
back stems to about 15cm during November.
Convallaria Cut
back stems to near ground level during November.
Convolvulus
Trim back herbaceous
perennial forms in March to keep within bounds.
Coreopsis Cut
back stems to about 15cm during November.
Cortaderia Cut
back half way to main clump in February. Wear gloves to protect hands
from razor-edged leaves.
Corydalis Cut
back stems to near ground level during November, earlier if self-seeding
is a problem.
Cosmos After the
foliage has died back cut back the stems to within 5cm of the ground in
March. Protect the crown with a layer of dry leaves or chipped bark in
winter.
Crambe Cut back
stems to about 15cm during November.
Crocosmia Cut
back flowering stems to near ground level in November, but leave
evergreen foliage to provide winter protection – removing it in early
March. In cold gardens, lift corms in October.
Cynara Avoid the
temptation to remove the faded flowerheads in autumn as they provide
interest in the winter garden. Cut them off only when they go brown and
soggy. Where temperatures fall below -15°C (5°F) protect the crown of
the plant with a layer of dry leaves or chipped bark.
Dahlia
Traditional advice dictates that once the first frost has blackened the
foliage, cut the main stems back to within 15cm of the ground and label.
Then, carefully lift and clean the tubers and allow them to dry
naturally indoors. Place the dry tubers in a shallow tray, just covered
with slightly moist potting compost, sand or vermiculite. Store in a
frost-free place, checking frequently over the winter months. However,
if grown on well-drained soils in milder gardens they can be left in
situ with the roots protected with a layer of dry leaves or chipped bark
in winter.
Delphinium Cut
back stems to 30cm of the soil during November and remove dead leaves
from around the crown. Cut back stems to near ground level in March.
Deschampsia Cut
back foliage in February before new shoots appear.
Dianthus Trim off
faded flower stems, but leave evergreen foliage. Large clumps can be cut
back to 15-20cm during March to keep compact.
Diascia Trim off
faded flower stems to their base during October. Cut back further if
necessary in March.
Dictamnus Cut
back stems to about 15cm during November.
Dicentra If not
already done, cut back dead foliage to near ground level in October.
Dierama Cut back
flowers to their base in November, but leave foliage until March. In
cold gardens, lift corms in October.
Digitalis If not
already done, cut back second flush faded flowering stems to near ground
level during October.
Doronicum Cut
back stems to near ground level during November.
Dryopteris Cut
back tatty fronds to near ground level in March.
Echinacea Cut
back flowering stems to near ground level during October.
Echinops Cut back
flowering stems to near ground level during November.
Epimedium Trim
off damaged leaves in February.
Eremurus If not
already done, cut down stems after flowering to near ground level in
October. Protect the crown with a layer of dry leaves or chipped bark.
Erigeron Cut back
stems to near ground level during November.
Eryngium Avoid
the temptation to cut back the flowerheads in autumn as they provide
interest in the winter garden. Remove them to their base during
February.
Erysimum Trim
lightly when flowers fade to keep plants compact.
Eupatorium Cut
back stems to near ground level after flowering.
Euphorbia If not
already done, cut faded flower stems to near ground level in October to
encourage bush growth, carefully avoiding new shoots from the crown.
Fargesia Cut back
tatty stems to ground level in March and thin others as necessary.
Festuca Comb
through the plant to remove dead foliage and trim off seedheads in
February, earlier if self-seeding is a problem.
Filipendula Cut
back flowering stems to near ground level during October.
Foeniculum If not
already done, cut back to 30cm in October and remove flowers to prevent
self-seeding. Tidy plants again in March.
Fragaria Remove
and burn disease-infected plants. Cut back leaves on healthy ones to
within 10cm of ground level in October.
Gaillardia If not
already done, trim stems to about 15cm of ground level in October.
Gaura Leave
flowering stems for autumn tints, then remove to their base in February.
Gentiana If not
already done, remove faded flowers to prevent rotting in October.
Geranium Cut back
deciduous varieties after autumn colour has finished during November.
Semi-evergreen varieties should be deadheaded only.
Geum Trim off
faded flowers and damaged leaves in November.
Gladiolus Before
the first frost, when the foliage starts to yellow usually October, cut
the main stem back to 3cm above the corm and carefully lift and clean
the and allow them to dry naturally indoors. Place the dry corms in a
shallow tray and store in a cool, frost-free place.
Gunnera Cut right
back during November and use leaves to protect the crown or insulate
with a layer of dry leaves or chipped bark.
Gypsophylla Cut
back flowering stems to near ground level during October.
Hakonechloa Cut
back to main clump during March before new shoots emerge.
Helenium Cut back
dead stems to near ground level during November.
Helianthus Cut
back faded flower stems to near ground level during October.
Helichrysum Cut
back stems to near ground level during March.
Helictotrichon
Cut back faded flower stems to main clump in March.
Heliopsis Cut
back to about 15cm during November.
Helleborus Trim
off dead or diseased leaves. Remove seedheads in November and again in
March.
Hemerocallis Cut
back faded flower stems to near ground level during October.
Hesperis Cut back
to about 15cm of ground level during November.
Heuchera Trim off
damaged leaves in March.
x Heucherella
Shear off faded flower stems in October. Trim off damaged leaves
in March.
Hosta Cut back
faded flower stems and leaves to near ground level during November.
Iberis Trim off
faded flower stems in October, but leave evergreen foliage.
Imperata Cut back
during March before new shoots emerge.
Incarvillea Trim
off dead foliage during October, protect the crown with a layer of dry
leaves or chipped bark.
Inula Cut back to
about 15cm of ground level during November.
Iris
(large-flowered) If not already done, cut back stems in each fan into an
arrow shape, with the tallest stem cut about 15cm from ground level
during October. Iris sibirica varieties should be left until March.
Knautia Cut back
the faded flower stems down to near ground level in October.
Kniphofia Cut
back faded flower spikes to near ground level. Protect borderline hardy
varieties by tying leaves together.
Leucanthemum Cut
back faded flower stems to near ground level in November.
Lamium Trim off
damaged leaves in February.
Lathyrus Cut back
everlasting peas to about 30cm from the ground during November. Then cut
back to about 15cm of ground level in March.
Liatris Cut back
to near ground level during November.
Ligularia Tidy
plants during November. Cut back to near ground level during March.
Limonium Cut back
to about 15cm during November.
Linaria Cut back
to about 15cm from the ground during November.
Linum Cut back
faded flower stems to ground level in November.
Liriope Cut back
faded flower spikes to near ground level during October.
Lobelia Trim off
dead foliage, protect the crown with a layer of dry leaves or chipped
bark.
Lupinus If not
already done, cut back second flush of faded flowering stems to near
ground level during October and remove dead leaves.
Lychnis Cut back
to near ground level during November.
Lysichiton Cut
back dead foliage in October. Remove self-sown seedlings as part of
routine border maintenance in early spring.
Lysimachia Trim
back yellow loosestrife to about 15cm of the ground in November, leave
Creeping Jenny until March.
Lythrum Cut back
to about 15cm during November.
Macleaya Cut back
to 15-20cm from ground level during November.
Malva Cut back to
about 15cm from ground level during November.
Matteuccia Cut
back tatty fronds to ground level in March.
Meconopsis Cut
back faded flower stems to near ground level in October, but leave the
foliage to protect the crown over winter. Remove leaves in March.
Melissa Cut right
back to about 15cm in October and insulate the crown with a layer of dry
leaves or chipped bark.
Mentha Cut back
tatty foliage in March. Use a sharp spade to cut around the plant and
restrict its spread.
Mimulus Insulate
the crown with a layer of dry leaves or chipped bark. Cut right back to
basal shoots in March.
Miscanthus Cut
back during March before new shoots emerge.
Molinia Cut down
tall species in November, leave smaller species until early spring.
Monarda Resist
cutting bergamot back in autumn since the stiff, vertical stems look
good all winter. Cut back to near ground level during February.
Morina Cut right
back to near ground level in October and insulate the crown with a layer
of dry leaves or chipped bark.
Nepeta Shear off
half way during November, then cut back to new shoots near the base in
March.
Oenothera Cut
back flower stems to about 15cm of ground level during November.
Omphalodes Cut
back to about 15cm during November, and insulate the crown with a layer
of dry leaves or chipped bark..
Ophiopogon Comb
through the plant to remove dead foliage.
Origanum Cut back
flower stems to new shoots in March.
Paeonia Cut back
herbaceous peonies to near ground level during November. Take care not
to tread on new buds at soil level.
Pennisetum Cut
back to main clump during March before new shoots emerge. To halt the
spread of the plant remove any unwanted self-sown seedlings as part of
routine spring border maintenance.
Penstemon Trim
off dead foliage to within 20cm of the ground in November, protect the
crown with a layer of dry leaves or chipped bark. Trim back to near
ground level in March.
Perovskia Shear
off flowers in November. Cut back to a balanced framework 30-45cm above
ground in March.
Persicaria Cut
back to about 15cm during November.
Phalaris If not
already done, cut back all but the youngest shoots to10cm of ground
level in October.
Phlomis Cut back
stems to about 30cm of the ground during November.
Phlox
Cut back to near ground
level
during November. Clear
away dead leaves to prevent carryover of disease.
Phygelius Remove
flowers in November. Cut back whole plant to about 15cm in March.
Physalis Cut back
to about 15cm of the ground during December.
Physostegia Cut
back to about 15cm of the ground during November.
Phytolacca Cut
back to near ground level in November. Always wear gloves since all
parts of the plant are poisonous and a potential skin irritant.
Platycodon
Insulate the crown with a layer of dry leaves or chipped bark. Cut right
back to basal shoots in March.
Pleioblastus Cut
back tatty stems to near ground level in March and thin others as
necessary.
Polemonium Cut
back to near ground level during November.
Polygonatum Cut
back to near ground level during November.
Potentilla Cut
back herbaceous species to about 15cm during November.
Primula Remove
tatty foliage in November.
Prunella Cut back
to about 10cm during November.
Pulmonaria Remove
dead and dying foliage during March.
Rheum Cut back to
near ground level during November.
Rodgersia Cut
back to near ground level during November.
Rudbeckia Cut
back to near ground level during November, protect the crown with a
layer of dry leaves or chipped bark.
Salvia Borderline
hardy varieties should trimmed and have their crown insulated with a
layer of dry leaves or chipped bark in October. Hardy varieties can be
tidied up in March.
Sanguisorba Cut
back tatty foliage in March. Prevent plant spreading by trimming around
crown with a sharp spade.
Saponaria Cut
back to about 15cm of the ground during November.
Sasa Cut back
tatty stems to near ground level in March and thin others as necessary.
Saxifraga If not
already done, remove faded flower stems to near ground level in October.
Scabiosa Cut back
faded flower stems to their base in October. Insulate the crown with a
layer of dry leaves or chipped bark
Schizostylis Trim
off faded flower stems to their base in November, in cold gardens
protect the crown with a layer of dry leaves or chipped bark.
Scrophularia Cut
back faded flower stems to 15cm in November.
Sedum Cut off the
stems at the base in March, taking care not to damage any emerging buds.
Senecio
(herbaceous) Cut back faded flower stems to their base in
November.
Sidalcea Cut back
to about 15cm of the ground during November.
Silene Cut back
faded flower stems to about 15cm of the ground in October.
Sisyrinchium Cut
back flower stems to their base during October, earlier if self-seeding
is a problem.
Smilacina Cut
back to near ground level in November.
Solidago Cut back
to near ground level during November.
Stachys Remove
dead and dying foliage during March.
Stipa Cut back
foliage in February before new shoots appear.
Stokesia Cut back
to about 15cm during November.
Symphytum Remove
dead and dying foliage during November. Always wear gloves since all
parts are a potential skin irritant.
Tellima If not
already done, cut back faded flower stems to their base in October.
Thermopsis Cut
back faded flower stems to about 15cm in October.
Teucrium Cut off
faded flower stems to their base in October. Cut half way back to main
clump in March.
Thalictrum If not
already done, cut back flower stems to their base during October. Cut
back the plants half way to main clump in March.
Tiarella Shear
off faded flower stems in October.
Tolmiea Remove
dead and dying foliage during March.
Tricyrtis Cut
back flowering stems to about 15cm during November .In cold areas of the
country provide a deep, dry, winter mulch around the crown of the plant.
Trollius Cut back
to near ground level during October.
Valeriana Cut
back faded flower stems to about 15cm in October.
Veratrum Cut back
flower stems to their base during November.
Verbascum Cut
back flower stems to their base in November.
Verbena Cut back
V. rigida and V. bonariensis to about 15cm in October and
insulate the crown with a layer of dry leaves or chipped bark. In cold
areas, lift roots in October and overwinter in boxes placed in a
frost-free place. Replant in spring.
Veronica Shear
back to about 10cm during November.
Veronicastrum If
not already done, cut back faded flower stems to their base in October.
Zantedeschia
Removed dead leaves during October, protect the crown with a layer of
dry leaves or chipped bark.
Zauschneria Cut
back flowering stem to about 15cm of the ground in October. In
cold areas of the country, provide a deep, dry, winter mulch around the
crown of the plant.
Happy gardening!
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