No rest for the wicked gardener. Here are some tasks for the month of May:
If you mulched, consider spreading some citrus peels among the chips to discourage cats, who like to use mulch as a giant litter box.
Garlic or mint planted around your rose bushes will keep aphids away.
Scrape your fingernails over a bar of soap before you go into the garden. That soap will wash away much easier than dirt will.
You can deadhead your bulbs, but leave the foliage until it turns yellow/brown. The bulb is storing food right now.
While you still have foliage to mark the spots where you have planted those bulbs, divide large clumps and move them into bare spots. Daffodils and narcissus can suffer from over-crowding.
The danger of frost should be past (although the weather has been very uneven), so it is probably safe to transplant warm weather vegetables and herbs into the garden. Although it is a good rule of thumb to wait until Memorial Day to put your tomatoes in the ground. Don't worry, they will catch up.
Check your clematis. It has probably had a growth spurt and needs tying up or guiding on its trellis or fence.
Remember to transplant or divide plants after the sun goes down or on cooler, gray days anbd water well. The plants won't suffer from so much stress as a result.
And, if you haven't yet this season, harvest the finished compost and turn the rest. Make sure it is wet enough to do its work.