There are a few differences between Mexican petunia plants and other petunias, but even though they’re different and have varying needs, they’re both beautiful and will grow and flourish for you if you’ve got the patience to make that happen.
The Mexican petunia is a flower that originated in Mexico, and escaped cultivation and spread to the Southeastern US by being seeded and pollinated from migrating animals. The plants grow in colonies of little stalks that come out of the ground, bearing one or two flowers and long blade-like leaves. They’re evergreen, which means that even if the flowers die off and fall away for the winter, you’ll still have green shoots in the ground, even in the snow.
These petunias do require sun—it’s recommended that you give them sun from somewhere between full and partial sun. Don’t keep them in shade though, they won’t grow very well for you. After flowering, you can choose to cut back your petunia stalks about halfway, and have an entirely new crop of Mexican petunia flowers. They love to bloom thoroughly and repeatedly. Mexican petunia plants are very aggressive when you give them an abundance of moisture and water, but they’ll resist drought and dry spells after they’re established.
Mexican petunia is great for ground cover, and will do well in sunny patches that need a splash of color anywhere in your garden—especially if you have a warm environment for your petunia.
Most other petunias aren’t evergreens. They generally grow in clusters, are picky about water, and have slightly higher demands about their environments. Most of them are pretty much cultivars of the same plant, rendering them different colors rather than completely different and unique plants.
These petunias can be grown from seed easily enough, and are good for planters—especially wave petunias. You can grow these each year, or you can try to salvage and propagate them yearly; it’s entirely up to your discretion.
Other petunias come in such a wide variety of colors that there are just too many to list here, but suffice it to say that there are colors from pinks and purples to yellows and reds, and everywhere in between. You can find these for cheap in the garden center nearest you, and usually you can plant them in groups.
Differences Between Them
The biggest difference is that Mexican petunias are evergreen perennials, while other petunias are usually considered to be annuals if planted outdoors because they don’t usually come back in the spring following a harsh winter. Mexican petunias are hardier, and they come in vivid colors of blue that seem to vibrate in bright sunlight.
Be careful, however; the aggressive nature of Mexican petunias can cause them to invade and take over the rest of your garden, stealing valuable sunlight, nutrients, space and water from your other plants. It’s best you keep your Mexican petunias in a container or bed, because they will end up all over your garden and become a pest if you don’t keep them under control.