Plant Bearded Iris
This is a good time of year to plant iris because you want to give them plenty of time to establish before cold weather. Also, some varieties are in bloom so you'll know what you're getting. Go easy on the manure but mix plenty of organic matter into the soil to improve drainage because iris will succumb if the soil is prone to staying wet. Dig a hole, mound up soil in the center of the hole, and lay the rhizome on top, spreading the roots. Just barely cover it with soil and firm the soil on top. Water well.
Once you've had your fill of rhubarb pies and crisps, harvest a surplus of stems, cut them into bite-sized pieces, and freeze them in freezer bags for future baking.
Watch for Lily Leaf Beetles
Bright red lily leaf beetles are easy to spot on lily leaves, and if you only have a few, you can pinch them between your fingers or knock them into a can of soapy water. The larvae usually feed on the undersides of the leaves, and they have a slug-like body covered with their black excrement (ugh). You might want to don gloves when squishing them. Neem spray is also effective against the larvae, and repeated sprays can kill the adults.
Give Plants a Dose of Aspirin
Aspirin water has been found to promote healthy growth and enable plants to stand up to insects and diseases. Dissolve 3 aspirins in 4 gallons of water and spray plants. One time is all that's needed.
Foil Slugs and Snails
Iron phosphate granules, sprinkled around plants, are an effective, nontoxic pesticide for slugs and snails. (Brand names include Escar-Go and Sluggo.) Coffee grounds and liquid coffee are also effective -- the higher the caffeine, the better.