Watch for slugs to appear. A little control now will lessen the need later. A small slug can do lots of damage to small seedlings in the garden.
Grafting is usually done this month as fruit trees begin to bud.
Cool season garden crops start going in this month.
Prune spring blooming shrubs such as Forsythia now as the blooms fade. Prune hard to encourage a natural shape which is easier to work with than round or square shapes.
Lawns will need food this month after winter rains have depleted nitrogen. A good slow release fertilizer will feed without pushing rapid growth and reduce the number of applications per year.
Plant bare root fruits and berries available in garden centers now. Bare root season will probably end by the middle of next month.
Tender plants stored from last fall, such as begonias, dahlias, and gladiolas can be planted now. Store tuberous begonias indoors. Add to the collection with a fun visit to the garden center.
Divide daylilies, hostas, astilbe, and dahlias which need dividing. Peonies seldom need division. It is better to simply buy more if you need more.
Trees and shrubs need their spring fertilizer application now. A general fertilizer, whether organic or inorganic, is fine. Apply specific applications as per plant type, and do it again later in May.
Turn the compost and if ready, apply and work into the garden. Use enough; many gardeners do not. Soil texture is the most important factor of success! Compost can be bought in bulk.