If soil and light conditions are right, Petunias self-seed readily. The secret is to avoid accidentally weeding tiny petunia seedlings in late spring.

Self-seeded petunias germinate around Memorial Day here in USDA Hardiness Zone 6. Right when spring rains start to dry out and the air temperature is on the rise.

Petunia seedlings outgrow weeds in late spring. The seedlings become established before summer annual weeds, such as crabgrass and lamb’s quarters.

Here’s the original planting from three years ago. Note how the flowers are the same color before (below) and different colors after (above).

I added five additional Wave Petunias this year. The Wave Petunias are the purply-lavender flowers on the bottom right.

If you’re letting your petunias self-sew, be patient. Initially, the tiny seedlings seem to take forever.

However, you’ll begin seeing flowers in a few weeks, and the fun begins.

Self-Sown Petunia Flower Variations

I enjoy the variation of colors and shapes of self-sewn petunias more than planting one cultivar. Note the pinks, whites, and a gradient from pink to white.

White with a touch of lavender and rounded petals.

A bold lavender pink. Note the white center.

Deep red with pointy petals and a lighter-colored center.

Lavender-to-white gradient with a white center and pointed petals.

Lavender-to-white gradient with a white center and rounded petals.

Tips for Self-Seeding Petunias

I haven’t mulched my gardens for a few years. The lack of mulch may be why petunia seedlings thrive.

I can’t say if petunias will self-sow if you mulch around the plants.

Where to Plant Petunias

Petunias like soil on the drier side, although once in bloom, I water and fertilize them regularly with bloom booster.

Although petunias like full sun, they tolerate less light. The petunias below are growing in partial shade.

I plant petunias and other annuals next to a walkway or seating area where they can be viewed often.

Can Petunia Self Seed in My Garden?

The first year my pansies self-sowed, I was unsure how they would do. They grew only because I didn’t weed for a few weeks, giving the seedlings a chance to grow.

Initially, I thought there weren’t enough seedlings to fill the space.

I also believed self-seeded petunias wouldn’t look as good as plants from the garden center.

I was wrong on both counts.

If, by chance, the petunias seedlings don’t make it, you can always fill in with some fresh plants from the garden center.