The Second Spring for Smart Gardeners
September's cooler temperatures and reliable rain make it the best month of the year for planting trees, shrubs, and perennials — even better than spring.
What September means
September is arguably the most underrated month in the garden calendar. Cooler temperatures, shorter days, and autumn rain create ideal conditions for transplanting trees, shrubs, and perennials — roots establish through fall and winter while the plant is dormant above ground, giving a significant head start over spring-planted specimens. Spring-blooming bulbs go in the ground from late September through November. Cover crops like crimson clover and winter rye can be sown on empty vegetable beds to prevent erosion, suppress weeds, and add organic matter when tilled under in spring. The vegetable garden still produces, with cool-season crops thriving in the gentler conditions.
September tasks
08- 01 Plant trees, shrubs, and perennials — fall planting gives roots months to establish before summer stress
- 02 Plant spring-blooming bulbs (tulips, daffodils, crocuses, alliums) 6–8 weeks before ground freezes
- 03 Sow cover crops (crimson clover, winter rye, field peas) on empty vegetable beds
- 04 Divide and transplant peonies, daylilies, and hostas while soil is still warm
- 05 Harvest winter squash when stems dry and skins resist a fingernail scratch
- 06 Bring tender houseplants back indoors before nighttime temperatures drop below 50°F
- 07 Aerate and overseed lawns — early September is the single best window for cool-season grass renovation
- 08 Clean up spent vegetable plants and add disease-free material to the compost pile
Plants to start in September
08- Tulips (plant bulbs)
- Daffodils (plant bulbs)
- Crocuses (plant bulbs)
- Alliums (plant bulbs)
- Garlic (plant cloves late September)
- Trees and shrubs (container or balled-and-burlapped)
- Perennials (mums, asters, sedum)
- Cover crops (crimson clover, winter rye)
Design tips for September
04- 01 Plant in groups of odd numbers (3, 5, 7) for a natural, non-regimented look when adding perennials and shrubs
- 02 Use September's fall color preview to plan where you need more deciduous trees or shrubs with autumn interest
- 03 Install landscape lighting while the ground is soft — trenching in frozen soil is miserable
- 04 Plant evergreen hedges now so they root in over winter and provide immediate screening next spring
Render this month's plan on your real yard
Upload a photo and Arden previews how the september additions land before you dig.
Frequently Asked Questions
01 What should I plant in September?
September is prime time for trees, shrubs, perennials, and spring bulbs. Plant garlic cloves for next summer's harvest. Sow cover crops on empty beds. Direct-sow cold-hardy greens (spinach, mache, claytonia) for overwintering under row covers.
02 Why is fall planting better than spring for trees and shrubs?
Fall-planted trees and shrubs benefit from cool air temperatures that reduce transplant stress, warm soil that promotes root growth, and reliable autumn rain. Roots grow actively until soil temperatures drop below 40°F, giving months of establishment that spring-planted trees miss.
03 When should I plant spring bulbs?
Plant tulips, daffodils, and crocuses from late September through early November, at least 6–8 weeks before the ground freezes. Bulbs need this cold period to vernalize. Plant at a depth of 2–3 times the bulb's height, pointed end up.