Reduce Rose Diseases
Watering roses with soaker hoses or drip irrigation will keep water off the leaves and help reduce the spread of black spot disease.
Leave Clippings on the Lawn
If you mow your lawn frequently you can leave the grass clippings on the lawn. If you prefer to bag them, remember that grass clippings can be used as a mulch in flower beds and vegetable gardens if you allow them to dry before use. Make it a rule to never use clippings from a lawn treated with herbicides.
Plant Veggies in Containers
Most vegetables and herbs can be grown in containers, so if you have limited space or only a few sunny spots in your garden, try planting in containers. You can even have a theme garden, which is especially fun for kids. Make a "Pizza Planter," "Salsa Planter," "Salad Planter," "Snack Planter", etc. The possibilities are endless.
Transplant Late-season Perennials
You still have time dig up and divide those late-season perennials (move 'em and feed 'em); they'll bloom right on schedule if transplanted now.
Take Softwood Cuttings
Mid to late June is an excellent time to take softwood cuttings of shrubs to start new plants. Some shrubs which can be propagated in this way include spirea, lilac, and viburnum.