Garden flowers in September: sowing, planting and flowering

What is sown, planted and pruned in September, and which annuals, summer bulbs and flowering shrubs are in flower, depends on your last spring frost. Below is the typical city of each climate — or open your own city’s frost dates.

Garden flowers in September, by climate:

• Late spring: last frost in late April or May (Veliky Novgorod): Bearded Iris, Crocus, Daffodil, Grape hyacinth, Hellebore and 28 more
• Moderate: last frost in April (Mannheim): Common honeysuckle, Marigold, Edging lobelia, Sweet alyssum, Busy Lizzie and 15 more
• Mild: last frost in March (Nagoya): Marigold, Nasturtium, Ageratum, Zinnia, Petunia and 3 more
• Warm winter: frost only now and then (Ravenna): Scarlet sage, Ageratum, Zinnia, Petunia, Celosia and 1 more
• Southern hemisphere: spring from September (Salta): Zinnia, Sunflower, Ageratum, Scarlet sage, Celosia and 22 more

Dates are for the typical city of each climate by the Greenly calendar’s rules: sowing and planting from the last spring frost (frost-hardy plants about three weeks before it, the rest a week after it once the soil is warm), autumn planting a month before the first autumn frost; annuals and summer bulbs flower after the card’s days to the first flowers for the card’s length of flowering, until the first autumn frost; flowering shrubs by the card’s days after the last spring frost. Perennials and autumn bulbs flower once established, so their flowering is not dated here.