Sweet Williams can grow in a wide range of zones from 3-8. They’re a second-year, late spring bloomer, but, unlike foxgloves, they need full sun to thrive.

Honesty (Lunaria Annua)
Honesty

This self-seeding biennial does well in specific zones (plant between 4-8) and is a strong mid-spring bloomer, although it does bloom in the second year. While I suggest you plant these in part shade, there’s nothing wrong with growing them in full sun.

California Poppy (Eschscholzia Californica)
California Poppy

California poppies are the perfect candidate for extremely warm zones like 8-10, otherwise, spring sowing is better. They obviously need full sun and bloom from early to mid spring, which is a considerably short blooming period.

Wallflower (Erysimum Cheiri)
Wallflower

Forget-Me-Not (Myosotis Sylvatica)
Forget-Me-Not

Forget-me-nots can thrive in a wide range of zones, be it 3 or 9. They bloom in early to mid-spring, and bright sunny conditions can help them produce even more colorful flowers.

During extreme heat, however, it’s best to move them away from the sun and underneath some shade.

And while you’re sowing seeds, don’t forget your indoor plants. Summer is the perfect time to prune these houseplants and encourage fresh growth.

Floral arrangement in containers

No matter how much somebody tries to convince you that August is a useless month for sowing flowers, DO NOT fall for it! There are plenty of hardy annuals and biennials that thrive in the warmth of August and can withstand the change in conditions that follows soon after. Sweet William (Dianthus Barbatus)