The Heat-Tolerant Trailing Plant That Thrives In Full Sun

If you have hanging baskets or a container garden, few things are more perfect than trailing plants covered in flowers. Sadly, some trailing plants, like begonias, will struggle with full sun in warm climates, causing your beautiful displays to fizzle out as the summer goes on. With the right plants, however, your garden can hang in there all summer long no matter how much heat or sun it gets. One of the best heat and sun tolerant flowers to pick for spilling over the sides of garden walls, containers, and baskets are petunias, specifically those with a trailing or cascading habit.

Petunias (Petunia x hybrida) are perennials in zones 10 and 11 but are grown as warm season annuals in most USDA zones. When picking out your flowers, note that not all petunias have a trailing habit, so stick with cultivars like those in the 'Flash Mob' or 'Avalanche' groups — they are known for their ability to cascade elegantly. Million bells (Calibrachoa x hybrida), a relative of true petunias, are also sometimes referred to as trailing petunias. While they look quite similar to petunias, million bells are generally shorter and have smaller flowers. But don't worry if you accidentally bought million bells instead of actual petunias for your hanging basket; they thrive in the same scorching summer sun their larger relatives grow well in. 

When buying petunias for your garden, you can either purchase young starts to transplant or buy seeds and start the cheerful flowers yourself. Regardless of which strategy you opt for, pick a cultivar that's bred for heat tolerance — a quality many older cultivars lack. Because petunias aren't very cold tolerant, it's important to wait until your soil has warmed to around 60 degrees Fahrenheit before planting them outside. 

After planting, provide your petunias with plenty of fertilizer and water. Like other plants grown in containers and baskets, petunias require more water than they would if they were grown in the ground. The same is true for fertilizer. Weekly fertilizing is especially important for cascading (also known as spreading) petunias. But while regular watering is a must, growing these plants in waterlogged soil is a mistake that will kill your petunias before you even get a chance to enjoy them. 

Don't forget to deadhead your petunias as well. Doing so will help encourage them to produce more blooms. Don't just remove the spent flower; be sure to pluck off the seeds below the petals, too. With good care, your petunias should thrive and bloom all summer and well into autumn. 

Petunias that trail or cascade are perfect for providing that "spiller" element in a classic "thriller, filler, and spiller" container garden formula. Pair them with colorful gladioli or other bold flowers that love the heat and sun as much as petunias, and you're sure to end up with an eye-popping planter. In hanging baskets, cascading petunias are showstoppers on their own, but you can pair them with other plants, too.

It might be tempting to crowd your basket or container with plants, so it instantly looks full and lush. However, it's essential to give your young plants enough space to grow and thrive if you want them to look nice all season. Resist the temptation to squeeze more than around five plants into a container with a 1-foot diameter. It won't take long for your fast-growing petunias to fill in and give you a basket overflowing with colorful flowers.