March Springs Into Season

Froggy frenzy

Froggy frenzy, M J Richardson, CC BY-SA

February has been unrelentingly wet and windy. The ground is saturated and mud is everywhere. Prolonged periods of soil saturation will reduce the level of oxygen accessible to plants leaving them vulnerable to rotting roots, yellowing leaves and eventually death. Curiously excess moisture in the soil can also reduce water uptake leading to further stress. Emerging spring bulbs and blossoms are damaged by the weather too. Blossoms are ripped from their branches, petals torn from their stems and those that remain brown and rot in the inclement weather. Putting up wind barriers, fencing and hedging and staking vulnerable plants will provide some protection from wind. Improving drainage by adding compost and manure or digging in horticultural sand will improve drainage in waterlogged soils. Raising planted pots on feet will allow excess water to escape and help prevent root rot.

March heralds the beginning of spring, days can be warm and balmy but the weather can also turn wintery, confusing and threatening plants and wildlife. A flurry of shoots, swelling buds and early blossom are the sure signs of new growth. Drifts of narcissi, both wild and cultivated, dance in the winds, their sunny colour brightening gardens, parks and grassy banks. March brings out frogs and toads from hibernation to frantic mating activity. Breeding takes place in ponds and their deep croaks ring out on warm nights as they seek a mate. Birds too are looking for mates and nesting sites, and fox cubs are born in their hidden earths.

In the garden

Narcissi at dawn 1

Narcissi at dawn 1, Jonathan Billinger, CC BY-SA

Narcissi are the stars of early spring. A ring of petals, some reflexed or bent backwards, surround a central trumpet. They spread in drifts, covering lawns, borders and open countryside, dancing on slender stalks in the spring breezes. Many are delicately scented - the small white flowers of Narcissi Thalia; Narcissi Silver Chimes, with its short, pale yellow trumpet and white petals; Narcissi Minnow, which has pale yellow petals and deeper yellow trumpets; and Narcissi Geranium with large cream petals and a short orange trumpet, are but a few of the scented varieties.

Star magnolia in Kew Gardens

Star magnolia in Kew Gardens, David Hawgood, CC BY-SA

Early blossoms are beginning to appear against a backdrop of skeletal, leafless deciduous trees. Some cherries flower early, their blossoms appearing before the leaves emerge. Prunus Kursar has deep pink single flowers; Prunus Beni-yutaka with clusters of fragrant pale pink flowers; Prunus cerasifera Nigra is covered in small, pale pink flowers with a darker eye; and Prunus The Bride with its single white flowers, are a selection which flower in March. Star magnolia (Magnolia stellata) is lightly scented. Its large silky buds open to reveal star shaped, multi petalled white flowers. Serviceberry (Amelanchier lamarkii), a woodland shrub, has clusters of delicate, star shaped flowers opening just before the bronzed new leaves. Winter hazel (Corylopsis paucifolia) has scented, bell like, pale yellow flower on a twiggy frame. These flowering trees and shrubs lift us from winter’s greys with their bright colours and subtle scents.

Violet (viola odorata)

Violet (viola odorata), Anne Burgess, CC BY-SA

Many woodland flowers, with their origins in deciduous woodland, take the opportunity to flower early before the leaves of the trees emerge, reducing the levels of light and restricting the growth of understory plants. Leucojum aestivum Gravetye Giant, looking like clumps of tall snowdrop with nodding bell flowers on the tips of the stems. Pulmonarias, which flourish in the shade, often have spotted leaves and flowers from intense blue to murky pinks and even whites. Viola odorata, the native sweet violet, with small purple flowers grows from clumps of bright green, heart shaped leaves. Wood anemones (Anemone nemorosa) and its cultivars, grow from small rhizomes that spread slowly through the rich leaf mould under trees. The white flowers with pale yellow stamens and an underside flushed with violet pink, grow out from filigree leaves with dark, wiry stems.

Sowing hardy seeds

Once weed seedlings start to appear outside, it shows the ground is warm enough for sowing hardy seeds, but you can always start seeds off early in seed trays on windowsills or in a protected environment such as a greenhouse or polytunnel. Many annuals, perennials and herbs can be grown easily from seed and it’s the cheapest way to fill your garden, pots or balcony with plants. Seeds need moisture, warmth and oxygen to germinate; they don’t need fertilizer at this stage of their development. Fill a seed tray, small pot or any recycled container such as a tin or yoghurt pot with drainage holes, with soil or multipurpose compost. For plants that enjoy dryer conditions, add some horticultural grit to the mix. Tamp or press the compost down to form a firm surface for the seeds to sit on. Scatter seeds thinly onto the compost, most seeds will need a thin covering, so cover to about the same depth as the seed either with compost or grit. For smaller seeds this is just below the surface, larger seeds may need to be planted more deeply with a wider spacing. Once covered, water the surface well and cover the container with a purpose made lid or a transparent plastic bag. This will retain the moisture and the compost should not need watering again until the seedlings have appeared. Check the seed tray each day and once the seedlings appear, take off the cover. If the cover is left on the seedlings may rot. From now on the seeds will need regular watering - if sunny this may mean more than once a day to prevent the compost drying out. Once the seedlings have two sets of leaves they can be ‘pricked out’, the soil is loosened and they need to be gently lifted, holding onto a leaf not the stem, and potted singly in small pots. They will be vulnerable and may wilt at this stage but careful monitoring for a few days should mean they grow into healthy plants than can be transplanted into larger pots, window boxes or the garden.

Weeding

Two species by the roadside (ground elder and hedgerow cranesbill)

Two species by the roadside (ground elder and hedgerow cranesbill), Jonathan Billinger, CC BY-SA

Moist soil and warmth are perfect conditions for weeds to start growing. Many other plants will still be below the soil so there is little competition; the weeds like to get a head start. There are many garden weeds but they fall mainly into two sorts. Annual weeds, which grow, sow seed and die all within one year and perennial weeds, which are more persistent and come up year after year. These have broad, deep taproots (such as dandelion or dock) or long string like roots (like ground elder or bindweed). They are harder to remove as a new plant can grow from even a small piece of root left in the soil.

Weeding can be done carefully with a hand fork, loosening the soil around annual weeds to pull them out and digging more deeply around perennial weeds, perhaps with a ‘daisy grubber’ to try to get rid of the entire root. Weeds can also be removed with a hoe by pushing the blade against the plant and cutting it off just above the soil. Perennial weeds will not be killed in this way, as the plant will regrow from the remaining root, but over time it will prevent the plant photosynthesizing and it will weaken and eventually die off. If the ground is still very wet try to work from boards to prevent damaging the soil structure. Start weeding now and catch them while they are young, it will help later in the spring when the warmer weather encourages faster growth.

Slug control

Black slug

Black slug, Charles J Sharp, CC BY-SA

At this time of year slugs can have a field day on fresh young leaves, particularly when the weather is warm and humid. As perennials begin to grow, they are particularly vulnerable, slugs may make a meal of them before you have a chance to notice they are there. Hostas, salvias, delphiniums, gerberas, sweet peas, dahlias and many others are at risk. Slugs are soft bodied creatures, they mostly feed at night but their tell-tale slime trails indicate their presence.

It is impossible to fully control slugs as so many live in our gardens, however there are many forms of control. Simply going out at night with a torch and picking them off your vulnerable plants works well. Nemaslug, a biological control, which specifically attacks molluscs and does no harm to other creatures, is available to water onto soil. Traps and barriers can help too; an empty half grapefruit skin or a jam jar full of cheap beer and sunk into the soil will attract slugs, these then need to be emptied regularly. Copper tape around pots, crushed eggshell or prickly stems from plants such as brambles form barriers that slugs, with their soft bodies, dislike crossing. Newer eco friendly pellets made from sheep wool are now available and surrounding plants with bits of fleece can also form a protective barrier. Encouraging wildlife of the kind that likes to eat slugs by providing suitable habitat will help control populations. Some birds, frogs and toads, hedgehogs, ground beetles and slow worms all enjoy feeding on slugs.

Planting perennials

Pasque flower (Pulsatilla vulgaris)

Pasque flower (Pulsatilla vulgaris), Bernard Dupont from France, CC BY-SA

Early spring is a good time to plant perennials, the staples of the border. There is moisture from winter rains and the soil is beginning to warm up, good conditions for establishing new root growth. Perennials grow quickly, bulking up within a season so buying plants in small pots is economic, 9cm - 2 litre pots are ideal and even plants with only a small amount of top growth showing will soon fill out.

When choosing plants make sure you check the soil and aspect of the site. Is your soil sandy or clayey, is the position sunny or shady? Balconies can be inhospitable with both cold winds and strong sun so make sure you choose robust plants for these. Different plants are adapted to grow well in particular situations and will do less well if put in the wrong place, plant labels and nurseries will give you the information you need to select the right plants for the right place. When choosing to group plants together, think about ‘seasons of interest’ - choose plants with different flowering times so you have variety throughout the year. Select plants for pollinators, particularly flowers that provide nectar at times of the year when other flowering plants are scarce. Think about a colour scheme, leaf texture and scent.

To plant up an area with perennials first check their mature spread size and then calculate how many plants will be needed to fill each square meter. Some perennials are tall and narrow, some short but spreading, so understanding a plant’s growth habit is important in determining the gaps to leave between new plants. When you have your plants place them on the soil in their growing position so you can check the spacing and arrangement. Lift pots individually and dig a hole under each, slightly wider than the pot and water into the hole before sprinkling the base with a small amount of a balanced fertilizer. Place the pot in a bucket of water briefly, to ensure the soil is thoroughly moistened, remove the plant from the pot, tease out the roots gently, place in the hole, ensuring the soil in the pot is level with the surrounding soil and firm in all round. When you have finished planting all your plants, water the entire area thoroughly from the top.

The plants will be most vulnerable in their first few months so make sure they are watered if there is no rain and check regularly for pests and diseases. Soon they will be blooming, encouraging wildlife in and giving pleasure.

Feeding, mulching and protecting fruit

Apple blossom time

Apple blossom time, David Wright, CC BY-SA

Blossoms are beginning to appear, heralding spring and a fruitful autumn. All plants benefit from feeding and mulching, and fruiting plants in particular need nutrients to promote flowering and fruit production. To encourage leaf growth, root growth, flowering and fruiting, top dress the soil around fruit trees and bushes with a mixed fertilizer such as Blood, Fish and Bone in early spring. A few weeks later spread 10 cms of well rotted manure around the root area of the plant or tree, being careful not to let it touch the trunk or stem. This will help reduce weeds and competition and reduce evaporation, keeping the soil moist.

Blossoms can be vulnerable both to predation by insects and birds and by late frosts. Cover currant bushes with netting to protect them from hungry bullfinches and use fleece to protect blossoms, particularly cherries, apricots and peaches.

Container plant maintenance

Pot plants

Pot plants, Mike and Kirsty Grundy, CC BY-SA

You can grow plants in containers even with a very small outdoor space; windowsills, balconies, back yards and patios can all be brightened up with container grown plants. Early spring is a good time to plant containers, warmth and moisture encourage good root growth and plants establish quickly. Add a little slow release fertilizer when planting to feed your plants throughout the growing season.

Early spring is also the right time to repot plants that have outgrown their current container. Carefully extract the plant from its container, remove some of the old compost and tease out the roots, replant in a larger pot with fresh compost in the base and all around the root area.

Maintenance of containers is important throughout the year but particularly from spring and throughout the growing season. Irrigation is an issue in warm weather and pots will begin to need to be checked daily for their water needs. The nutrients in compost are soon used up so pot grown plants rely on regular feeding. Feeding should start in spring when the weather warms up roughly once every two weeks, increasing to once a week if plants are growing vigorously or if the weather is particularly warm. Liquid feeds are easier to use on containers, without over or under feeding. Always check the supplier’s instructions and then watch your plants bloom.

Creating a rainwater garden

Increasingly, urban green spaces such as front gardens and courtyards are being paved over. Run off from hard surfaces, buildings and roofs has traditionally been directed into sewers, and in heavy rain can overwhelm the drainage system and cause pollution and flooding.

Creating a rain garden can slow the flow from your downpipes and help to mitigate flooding during periods of high rainfall. Rain gardens are shallow basins, set over soil and planted with plants that benefit wildlife and can withstand short periods of flooding. Water is diverted from a downpipe through a gravel channel into the rain garden where it can soak into the ground and be absorbed by plant roots. The water is held in the garden by a raised edge or berm, an excavated, shallow basin is filled with soil mixed with sand and compost that will speed drainage, then planted out. Plants that will survive in a rain garden include Actea simplex, Anemanthele lessoniana, Anemone x hybrida, Bergenia cordifolia, Carex elata, Cornus alba, Cornus sericea, Cornus sanguinea, Dryopteris felix-mas, Iris ensata, Ligularia dentate, Lobelia cardinalis, Lythrum salicaria, Matteuccia struthiopteris, Persicaria bistorta, Polystichum setiferum and Valarian officinalis.

Rainwater gardens need to be at least 3m away from buildings, in direct or partial sunlight, have good drainage and be situated on a gentle slope to allow for run off. Alternatively a downpipe can be diverted into a raised bed filled with free draining soil with a gravel base and exit route for slowly draining rainwater either back into the drain or towards beds or grass areas.

Gardening tasks in March

Woody Plants

  • Coppice or cut back the stems of cornus and salix to encourage the growth of new, colourful stems for the following winter
  • Feed trees and shrubs with a balanced fertilizer such as Blood, Fish and Bone
  • Prune hardy evergreen shrubs and topiary
  • Plant mixed, native hedging
  • Prune bush and climbing roses
  • Tie in wall shrubs and climbers as the new growth emerges

Ornamentals

  • Lift and divide overgrown perennial clumps
  • Plant new herbaceous perennials
  • Lift and divide large clumps of snowdrops and aconites after the flowers have died but while still ‘in the green’, before the leaves die back. If buying “in the green” ensure the bulbs are cultivated, not foraged from the wild
  • Plant summer flowering bulbs such as gladioli, agapanthus, crocosmias and oriental lilies
  • Sow hardy annuals

Fruit

  • Check soft fruit bushes for aphids
  • Check blackcurrants for big bud mite
  • Net gooseberries from bullfinches
  • Finish any winter pruning of fruit bushes and autumn raspberries
  • Feed and mulch fruit trees and bushes
  • Protect the blossoms of cherries, apricots and peaches from frost damage with fleece
  • Sow alpine strawberries
  • Plant melon seeds under cover in the warmth

Wildlife

  • Hang bird and bee nesting boxes
  • Create rock and log piles for garden wildlife

Sustainable Practices

  • Protect new shoots from slugs with crushed eggshells, prickly twigs such as brambles, fleece, coffee grounds or beer traps
  • Put in stakes of cut hazel or willow to support plants before growth becomes too leggy and floppy
  • Hoe and mulch borders to control weeds
  • Check pots for watering, if the weather is warm they may begin to dry out
  • Top dress pots and containers

Relaxing reading

The Urban Wildlife Gardener

Emma Hardy

How to attract bees, birds and butterflies to your outdoor space.

Buy >

The Songs of Trees

David George Haskell

An exploration of ecology and the relationship between humans and nature through a sensual response to the lives of trees.

Buy >

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Things to see, places to go

Hearing Birds

An art installation to increase awareness of hearing loss to mark World Hearing Day.

date

2 - 3 March 2020, 12pm - 6.30pm

location

Dalston Eastern Curve Garden, 13 Dalston Lane, London E8 3DF

Learn more >

Gardening for Wildlife in a Changing Climate

Over a programme of talks experts will share their knowledge of building resistance and encouraging wildlife while mitigating the effects of climate change.

date

28 March 2020, 10.30am - 2.30pm

location

London Wetland Centre, Queen Elizabeth Walk, London SW13 9WT

Learn more >

Catriona Andrews

CATRIONA ANDREWS

Catriona is a landscape designer and environmental educator. Her work combines naturalistic planting and sustainable practices to create spaces that are sensitive to the environment and welcoming to wildlife. She designs private gardens, community gardens and public spaces and leads courses and workshops on garden and planting design and the environment.