How to Grow Petunias That’ll Make Your Neighbors Jealous
Last May, a woman from Schaumburg walked into Goebbert’s Farm & Garden Center looking pretty defeated. She’d killed three rounds of petunias the summer before and was ready to give up. “I just can’t grow petunias,” she told me. Turns out, she was making a common mistake of having too much shade and watering too much. Petunias are a popular flower for their vibrant colors and easy maintenance. However, they do require some specific care in order to thrive.
That’s what we love about petunias. Once you know the basics, they’re actually one of the easiest annuals to grow. At our garden center in Barrington, we’ve helped folks from Arlington Heights, Hoffman Estates, South Barrington, and Algonquin grow petunias successfully for years.
Why Grow Petunias in the First Place?
Here’s the thing about petunias – they give you massive color payoff for minimal effort. We’re talking blooms from late spring clear through fall frost. That’s five or six months of flowers from one planting. Try getting that from most other annuals.
Petunias come in pretty much every color you can imagine. Purples, pinks, reds, whites, yellows, and wild bi-colors that look almost tie-dyed. A customer from Arlington Heights plants nothing but purple and white petunias in her window boxes every year. Simple combo, but the purple and white contrast stops people walking by.
Petunia Growing & Care Guide PDF
Choosing the Right Petunia Type
Not all petunias are created equal. When you come into Goebbert’s, you’ll see a few different types, and picking the right one matters for how you want to grow petunias in your space.
Grandiflora Petunias have the biggest flowers – up to 5 inches across. Gorgeous, but they can get beat up by heavy rain. Best for covered porches or spots with some protection.
Multiflora Petunias have smaller flowers but way more of them. These handle rain and wind better than grandifloras. Great for garden beds where they’ll get exposed to weather.
Wave and Spreading Petunias – this is where the magic happens. Wave petunias and similar spreading types grow fast and wide – one plant can spread 3-4 feet. They’re perfect for hanging baskets, spilling over containers, or covering ground.
Grandiflora – biggest blooms, best for protected spots
Multiflora – more flowers, handles weather better
Wave – spreads 3-4 feet, perfect for baskets
When to Plant Petunias in Illinois
Timing is everything when you grow petunias around here. Our last frost date in the northwest suburbs is typically mid-May. Don’t jump the gun – petunias hate cold soil. A late frost will set them back weeks or kill them outright.
We start stocking petunias at Goebbert’s in late April. You can buy them then and keep them in a protected spot until planting time. Just bring them inside if temps drop below 40°F at night. Most years, Memorial Day weekend is the safe bet for planting here in the Chicago suburbs.
Sunlight Requirements
Petunias want full sun – at least 6 hours daily. More is better. That south-facing porch? Perfect. Shady north side of your house? Skip the petunias and check out our astilbe or coral bells instead.
They’ll tolerate 4-5 hours of sun, but flowering drops off noticably. And leggy, stretched-out petunias aren’t what anybody wants.
Soil and Drainage
Good drainage matters more than perfect soil. Petunias will rot in soggy conditions faster than you’d think.
If you’re planting in containers (and most folks in South Barrington do), use quality potting mix – not garden soil. For garden beds, work in some compost before planting.
Clay soil? Add extra organic matter to loosen things up.
Planting Your Petunias Step by Step
Here’s our tried-and-true method for getting petunias off to a strong start:
- Dig a hole about twice as wide as the root ball
- Gently remove the plant and loosen any circling roots
- Set the plant at the same depth it was growing – don’t bury the stem
- Fill around with soil and press firmly to eliminate air pockets
- Water deeply right after planting
That initial deep watering is crucial. We see too many dead petunias because folks didn’t soak them in properly after transplanting. Space regular petunias about 12 inches apart. Wave and spreading types need 18-24 inches because they tend to get big.
Watering Tips to Grow Petunias Successfully
Here’s where that customer from Schaumburg was going wrong. She was watering her petunias every single day – just a little sprinkle. Petunias actually prefer deep, less frequent watering. Soak them thoroughly, then let the top inch of soil dry before watering again.
Container petunias need more attention than in-ground plants. On hot July days, hanging baskets might need water twice daily. Stick your finger in the soil – if it’s dry an inch down, it’s time to water.
Feeding Your Petunias
Petunias are hungry plants. They bloom constantly, which takes energy. Feed them every 2-3 weeks with a balanced liquid fertilizer, or use slow-release granules at planting time.
Signs of underfed petunias include pale leaves, fewer blooms, and weak growth. If your petunias look tired by mid-summer, bump up the feeding.
The Secret – Deadheading
Want to know the real secret to petunias that bloom all season? Deadheading. That’s just a fancy word for removing spent flowers.
Here’s what regular deadheading gets you:
- More flowers, continously through the season
- Bushier, fuller plants that don’t get leggy
- Better resistance to disease
- Neater appearance overall
Common Problems When Growing Petunias
Leggy, Stretched Growth – Usually means not enough sun. Could also mean too much fertilizer (nitrogen makes them grow leafy, not flowery). Cut them back by half in mid-summer and they’ll regrow bushier.
Yellowing Leaves – Check your watering. Yellow leaves at the bottom often mean overwatering. Yellow leaves overall might signal nutrient deficiency – time to fertilize. Our seasonal fertilizing guide covers this in more detail.
No Blooms – Nine times out of ten, it’s a light problem. Petunias need full sun. Could also be overfertilizing with high-nitrogen plant food – switch to a bloom-booster formula.
Best Spots to Grow Petunias Around Your Home
We help customers from all over the northwest suburbs figure out where petunias work best. Sunny window boxes are classic – they spill over beautifully and greet everyone who visits. Hanging baskets on front porches get great light and show off trailing varieties. Container groupings on patios create instant color, and you can move them if needed.
Garden bed edges work great for multiflora types. Mix petunias with sedum or other perennials for a combo that gives you annual color plus long-term structure. A family from Hoffman Estates does this along their entire front walkway – petunias in front, Autumn Joy sedum behind. Looks amazing from spring through fall.
Shop Petunias at Goebbert’s This Spring
We stock an incredible selection of petunias every spring at Goebbert’s Farm & Garden Center in Barrington. Our inventory hits peak around late April through June – that’s when you’ll find the best variety of colors and types. We carry everything from classic grandifloras to Wave spreading varieties to unique bi-colors you won’t find at the big box stores.
Our staff knows how to grow petunias – we’re gardeners ourselves, not just shelf stockers. Bring your questions. Show us photos of your space. We’ll help you pick the right petunias for your specific situation, whether you’re in Barrington, South Barrington, Schaumburg, Arlington Heights, Hoffman Estates, or Algonquin.
Stop by this spring and let’s get your porch, patio, or garden beds overflowing with beautiful petunia blooms!