Prune now or AFTER flowering: early flowering clematis (Montana), Akebia quinata (chocolate vine), Abelia, Arbutus (strawberry tree), Camellia, Choisya (Mexican orange blossom), Chaenomeles (Japanese flowering quince), Hibiscus, Kerria japonica, Prunus (laurel), Forsythia, Ribes (flowering currant), Spirea, Viburnum tinus, winter jasmine. Also prune any shrubs from my April diary post that were still hanging on in flower and so were not pruned in April.
Watch out for frosts. May can hold frost surprises when you least expect it.
Feed plants. Everything is springing into life, using lots of energy, requiring a food boost for new shoots. A general balanced feed will cover all bases.
High nitrogen (N) promotes new shoot development.
High phosphorus (P) promotes new root growth.
High potassium (K) promotes fruit and flower growth.
Fish, blood & bone is a good organic slow release fertiliser.
Bonemeal boosts roots when planting new shrubs. Coat roots of new plant in Mycorrhizal fungi to increase plant’s potential for taking up water and nutrients.
Give acid loving plants, (azaleas, rhododendrons, camellias, blueberries) a boost with ericaceous feed.
Feed flowering plants with high potash fertiliser to prolong flowering period.
Annual weeds. Gently hoe / agitate soil surface or pull shallow roots. Be careful to avoid new seedlings and existing plants. Deep digging will bring dormant seeds to the surface and actually create more weeds so try and keep soil disturbance to a minimum. Regular weeding will prevent weeds going to seed and reduce spread. Look out for annuals such as annual meadow grass, annual nettles, hairy bittercress, groundsel, chickweed, speedwell, cleavers, fat hen, shepherd’s purse, and creeping oxalis & buttercup.
Tackle perennial weeds such as ground elder & bindweed. Avoid chemicals - organic methods are always best for you, your garden and the environment. If you cannot avoid chemicals then carefully treat specific area, wrap in a plastic bag to contain it whilst still attached to parent plant so systematic weedkiller can work its way to the roots; otherwise dig out as much as possible, try to untwine from border plant roots. Virtually impossible to dig out completely as even an inch of root left in ground re-grows but new plants will have weaker/unestablished new roots so easier to remove and over time the problem can be managed and maintained. Digging out needs to be regularly repeated.
Remove tap rooted weeds with a specific taproot tool to avoid disturbing soil and plants around the weed. Try to remove entire taproot or it will re-grow. An alternative to glyphosate is pelargonic acid (naturally occurring in geranium leaves) used in Richard Jackson’s double action weedkiller or try spraying with vinegar which contains acetic acid.
Leave spring-flowering bulbs foliage to naturally die down. Divide overcrowded clumps.
Always check hedges for nesting birds if planning to cut back/tidy up.
Plant up containers & hanging baskets; water and feed container plants regularly.
Look out for pests & diseases on plants i.e. lily beetle, rose black spot.
Harden off courgettes, pumpkins, and tomatoes. Thin out carrots, lettuce, beetroot. Earth up potatoes.
Harden off annual bedding. Leave out in shade in the day & return indoors at night to avoid frost.
Lay down straw around strawberries to stop forthcoming fruit rotting. Net soft fruits to deter birds.
Check gooseberry bushes for sawfly caterpillars.
Look out for slugs and snails on new shoots! Either pick off, use beer traps, copper rings, shingle/egg shells, nematodes ‘Nemaslug’. If using slug pellets try to use organic ferric phosphate (child & pet friendly) I personally use Sluggo Slug & Snail Killer by Neudorff, certified for organic gardening; this can be used on edible crops also resistant to rain. Avoid metaldehyde-based products.
Gardens are delicately balanced ecosystems so try not to totally eradicate pests as they will be a food source for other creatures i.e. birds/frogs love slugs & snails! Everything co-existing, with no dominant species, will equal a healthy garden.
Ponds: remove duck & blanket weed. Remember to leave it on side of pond so wildlife can crawl out.
Best to water in morning or eve but note evening watering can attract slugs and snails! Plants can use water most efficiently at beginning or end of day; less lost to evaporation, foliage will not scorch in sun if water splashed on them. Use rainwater if possible.
Keep greenhouses ventilated.
Plant out dahlia tubers end of May when frost risk has passed or wait till early June.
It’s Chelsea Chop time! Some perennials can be cut back by a third to a half at the end of May. e.g. Echinacea purpurea, Helenium, upright Sedums, Rudbeckia, Phlox paniculata, Asters, Penstemon, Nepeta. This will delay flowering but create a longer flowering period and a denser, compact plant. If that seems a little drastic then just chop half the plant to stagger flowering.