planting guide and calendar from New York Botanical Garden

I just looked over the New York Botanical Garden site and they have a great planting guide!  For example, here's what they recommend for September:

September Gardening Tips

Planning

• Complete ordering spring-flowering bulbs and other plants for fall planting
• Continue to assess areas in the garden that may need additional planting
• Continue to work on a landscape plan for fall planting of trees and shrubs
• Continue to take garden notes and/or photographs to plan future plantings

Chores and Maintenance

• If rain is still lacking, continue to practice water-wise horticultural techniques
• De-thatch and aerate existing lawns to promote root growth
• Mow lawns regularly to keep grass at 2 ½" height
• Complete lawn restoration before September 15
• Collect seed from perennials and annuals
• Continue to cut flowers for drying: yarrow, strawflower, gomphrena, cockscomb, etc.
• Remove and compost spent annuals and fallen leaves
• Continue to aerate and moisten compost pile to speed decomposition
• Continue to check for insect pests and treat accordingly
• Continue to remove any fallen leaves and debris that can harbor insect pests and disease organisms
• Continue to apply deer repellent
• Take in tender aquatic plants and tropical fish from ponds
• Begin to feed birds

Planting

• Plant and transplant broad-leaved and needle-leaved evergreens through October 15
• Continue to propagate herbs from new growth and transplant into pots for winter use
• Continue to divide and transplant early-blooming perennials
• Divide daylilies after flowering
• Plant lilies
• Sow hardy annuals in prepared planting beds
• If weather is cool, begin planting spring-flowering bulbs but wait until late October to plant tulips
• Plant late-season annuals like ornamental kale and cabbage for fall color
• Sow parsley, radish, lettuce, carrot, and onion
• Complete planting out seedling biennials

Pruning/Fertilizing

• Prune rambler roses
• Prune to remove any diseased and dead rose canes
• Root prune wisteria that doesn't bloom
• Add organic matter such as manure, compost and/or leaf mold to improve garden soils
• Fertilize roses one last time
• Fertilize lawns with organic fertilizer to stimulate winter root development

Indoors

• If frost threatens, take in houseplants and pinch back houseplants before returning them indoors
• Check houseplants for insect pests and treat as necessary before bringing them in
• Begin to force poinsettias for Christmas. Move indoors to a sunny location and cover for 14 hours each night for a period of 6-10 weeks
• Take cuttings of begonias, geraniums, solenstemon (coleus), etc. to grow on as houseplants