This is the MAY installment of Horticulture Week's month-by-month guide to essential maintenance and management tasks for parks, gardens and grounds maintenance staff.

Update pesticide records
Update sowing records
Undertake visitor analyses – who is visiting, from where and what was their experience
Hire in seasonal workers as needed for mowing and weeding duties

Protect tender plants from night frosts
Control slugs and snails
Water plants as needed
Control weeds
Apply mulches
Check irrigation systems are functional

Trees, shrubs and hedges
Top up mulches around newly planted trees and shrubs
Lightly trim box and formal evergreen hedges
Prune spring-flowering shrubs such as kerria after flowering
Take softwood cuttings from shrubs
Note where more shade is needed

Beds and borders
Stake and tie
Train sweet peas
Clear spring-flowering bedding and prepare ground for summer subjects
Sow biennials such as sweet Williams for next year’s spring bedding
Sow perennials such as achilleas outdoors
Harden off summer bedding ready for planting out
Thin annuals from earlier in situ sowings
Divide early primulas after flowering
Cut back and divide pulmonarias and doronicum

Wall plants
Tie in new growth
Prune Clematis montana after flowering
Prune pyracanthas

Continue deadheading spring bulbs and apply organic fertiliser

Remove spring bedding
Plant up summer displays in the south but wait until June in the north
Harden off planted hanging baskets

Greenhouses and conservatories
Ventilate and damp down regularly
Provide shading for the summer
Check regularly for pests and diseases
Plant up hanging baskets for the summer
Harden off summer bedding
Sow calceolaris and browallia for winter pot plants

Water features
Inspect regularly for algae bloom and treat accordingly
Top up as necessary

*Jobs should only be undertaken when ground and weather conditions are suitable and will vary according to location and may vary significantly from year to year. And remember that while the year nicely divides into 12 months, activities often overlap

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