The Ornamental Garden in May
This can be a very busy month subject to what you intend growing.
Providing all fears of late frosts has passed most bedding plants can be planted out this month.
As a rule of thumb, plant out the hardier annuals first, then follow these with the less hardy varieties.
At any time this month:
Inspect lilies for signs of Scarlet Lily beetles which are usually active at this time of the year.
Ensure that tall plants have adequate support.
Plant out Containerised shrubs, Roses and perennials.
Thin out congested Aquatic plants.
Week 18 - 30th Apr. to 5th May.
If not done previously apply a top dressing of general fertiliser in readiness for planting out.
Prune/Tidy up Fatsia japonica.
Be on the lookout for Lupin aphid.
Week 19 - 6th May. to 12th May.
Prepare bed for Dahlias.
Plant out Penstemon if conditions allow.
Stop (remove tip) established Dianthus chinensis.
Week 20 - 13th May. to 19th May.
Lift, replant or pot up self seeded Lunaria.
Place Canterbury Bells in coldframe to harden off.
Pinch out the growing points of Actinidia arguta and chinensis when quite young.
Spray Roses to prevent major outbreaks of pests and diseases.
Deadhead Pieris after flowering.
Commence Chrysanthemum stopping programme.
Week 21 - 20th May. to 26th May.
If not done previously prepare beds for planting out.
Plant out Agastache, Agrostemma, Anomatheca, Arthropodium, Calendula, Callistephus, Carnations, Centaurea cyanus,Chrysanthemum annuals, Dianthus chinensis, Echium, Eschscholtzia, Gaillardia, Godetia, Gypsophila, Helichrysum, Iberis, Lavatera, Limnanthes, Limonium, Linaria, Lobelia, Lychnis, Mimulus, Nemophila, Nicotiana, Nigella, Nolana, Orache, Papaver / Poppy, Phlox drummondii, Portulaca, Reseda, Rudbeckia, Salpiglossis, Salvia, Schizanthus, Silene, Tropaeolum/Nasturtium and Verbena if conditions allow
Place potted Camellias outdoors for the summer.
Layer Wisteria if required.
Divide Papaver / Poppy.
Pinch out the tops of Salvia to encourage branching.
Watch out for signs of leaf spot and rhizome rot on Bearded Iris.
Week 22 - 27th May. to 2nd Jun.
Plant out Ageratum, Alstroemeria, Alyssum, Amaranthus, Antirrhinums, Arctotsis, Bidens, Brachycome, Celosia, Cerinthe, Convolvulus, Cosmos, Dahlias, Gazania, Gerbera, Impatiens balsamina, Ipomea, Pacific Coast Iris, Laurentia, Lewisia, Marigolds, Mesembryanthemum, Nemesia, Nerium, Osteospermum, Pansy, Passiflora, Tagetes, Thunbergia, and Zinnia.
Keep Gladioli bed weed free.
Pot up Dahlias to grow as pot tubers.
Feed Aethiopica with a balanced liquid fertiliser at weekly intervals from now until August.