Britton’s wild petunia, sometimes known as Mexican petunia, was introduced and is very well-liked in the landscape industry. It has been planted all across the Southeast US. Since it can tolerate and even thrive in shade, sun, damp, dry, and bad soil, it is a common choice for challenging regions due to its beauty and tolerance of varied urban landscape conditions. Despite the development of sterile cultivars, all of them still need upkeep to stop escape because their creeping lateral roots will continue to propagate the disease.
Species Characteristics
Dark green, opposite, lance-shaped leaves with smooth or wavy margins, measuring 15–30 cm long and 1-2 cm wide.
Flowers: trumpet-shaped, pedunculate, 4–8 cm in diameter, borne singly or in clusters at the tips of the stems, often purple, but white and pink varieties are also available.
Cylindrical capsules holding 4-28 seeds are called seeds. The dehiscence of capsules is explosive, and the seeds are widely dispersed.
Impacts
spreads through lateral roots and a large number of easily viable seeds that can sprout in either light or darkness. When moist, the seeds secrete a gel-like material that when dried allows them to adhere to surfaces. It creates dense stands in the forest’s understory, displacing native species and changing fire and succession patterns.
Control Methods
Avoid planting. Be sure to control lateral spread if sterile cultivars are planted.
Mexican-petunia must be entirely eliminated, both above and below ground, or else it won’t respond to mowing, tillage, or weed eating the tops off. Instead, a shovel or other tool might be used to dig up the plant with the intention of removing the entire root mass.
Foliar: a 23 percent glyphosate product that frequently resprouts from lateral roots that creep up on it. It can take several sessions.
For more advice on management suggestions, speak with your neighborhood UF IFAS Extension. The following EDIS Publication has further information:
How can you prevent the proliferation of Mexican petunias?
A yard or garden bed can be swiftly overrun by Mexican petunias. Several measures can be taken to prevent Mexican petunias from encroaching in other places.
To slow down and restrict the spread of the plant, bury wood planks approximately six inches thick around it.
A larger Mexican petunia should be planted in a pot and placed in an established garden. Before the plant needs to be repotted, the roots will expand within the pot and let it to blossom wonderfully for years.
The plant will be forced to develop as a ground cover without encroaching on other parts of the garden if it is placed in a walled area far from other plants.
Mexican petunia seeds can disperse, so if you find a sprout in a spot where you don’t want the plant to grow, pull it out as soon as you can to prevent it from setting roots and creating a problem.
Mexican petunia: How can you get rid of it?
We apologize, but Mr. Smarty Plants needs some time to catch up after receiving an overwhelming amount of mail. Soon, we hope to be taking new inquiries once more. I’m grateful.
ANSWER:
I’m going to excerpt some of Mr. Smarty Plants’ recent response to a query regarding the eradication of Ruellia for you.
Ruellia brittonia, sometimes known as the Mexican Petunia, is a native of Mexico. The Florida Exotic Pest Plant Council has classified it as a Category 1 invasive species because it has invasive potential. Its rapid growth, copious seed production, and deep-rooted nature all contribute to its invasiveness.
To remove it from your garden, one method is to pull it out and continuously cutting back new sprouts. This is not always an easy operation, but you want to limit the use of herbicide in your garden. Additionally, you should remove faded blossoms to inhibit seed pod development and new seedlings as they emerge in order to prevent reseeding. Glyphosphate can be used as a chemical control strategy. Use this with extreme caution because it has the potential to destroy all of your other plants. Petunias should be cut to the ground and their stem stumps treated with glyphosphate. Make sure you adhere to the warnings and instructions on the label.
How are Mexican petunias thinned?
Tips for Pruning Mexican Petunias For making your cuts, a pair of hand clippers works great. Trim the stems of your Mexican petunias to a height of about 2 inches from the ground if they were damaged by a frost or if you want thicker plants. New stems will quickly form and reach their normal height.
How invasive is Mexican petunia?
Mexican petunias can bring beauty to your garden if you take care to select cultivars that are not invasive and that you can keep up with and manage.
blue-purple petunias? Mexican petunias may initially be mistaken for regular garden flowers.
Ruelliasimplex, a fast-growing perennial with green to purple stems and green leaves, are what Mexican petunias are in reality. This plant’s invasive, wild version is so aggressive that some states have prohibited it, while others have put it on a watch list of invasive plants. Mexican petunias are categorized as “extremely invasive” by the state of Florida.
Ruellia simplex, also known as R. tweediana, R. brittoniana, R. coerulea, and R. malacosperma, is a plant native to Mexico and western South America that can withstand freezing temperatures in USDA hardiness zones 8 to 11. Even though the plants were given their correct name by a German botanist in 1879, most horticulturists today call them R. tweediana. Mexican bluebell, hardy petunia, wild petunia, Britton’s wild petunia, and perennial petunia are examples of common names.
Mexican petunias may thrive in a variety of environments but prefer moist or marshy soils, such as those found at the edges of ponds and lakes or in moist woods. In dry soils, they can endure drought and even full sun.
The plants’ colorful, spectacular blossoms are fleeting, yet they bloom for a long time, starting in early spring and lasting until frost. The shrubs have an approximate width of one foot and a height of one to four feet.
Most of these lovely, hardy plants have the unfortunate drawback of spreading out of control and displacing good plants.
Invasive Mexican petunias develop thick, horizontal roots that extend above and below the surface of the earth, making them challenging to uproot. Even small portions that are missed can reseed. When ripe, seed capsules on the plants open and release seeds all over the place. Years after the plants have been eliminated, the seeds may still be present in the soil and begin to grow.
Even worse, when the seeds are moist, a mucous-like goo forms. They adhere like glue to dry soil once they are dropped there.
Mexican petunia varieties that gardeners can enjoy and cultivate responsibly have been developed by breeders. Because they are sterile cultivars, “Mayan Purple” and “Mayan White” do not produce seeds that self-sow.
‘Mayan White’
Mexican petunias are invasive, however “Mayan White” and its relative “Mayan Purple” are sterile substitutes.
Home Depot locations in Florida presently carry “Mayan Purple” and “Mayan White.” By 2014, the breeder, Rosanna Freyre, hopes to have the cultivars more widely accessible. This may involve cooperating with a North Carolina mail order business and a Georgia company with statewide distribution.
Another possibility is “Katie.” Due to its lovely blossoms and simplicity of maintenance, Texas A&M University has named this less aggressive, dwarf Ruellia a Texas Superstar.
‘Katie’ has blooms that are purple, pink, or white and grows to a height of about 6 inches. However, because it is fertile and spreads through seed, researchers from the University of Florida and the Institute of Food and Agricultural Services do not advise using it.
Can the Mexican petunias be reduced?
Typically, a Mexican petunia only needs one annual pruning in late winter or early spring to remove any damaged, weak, or unwelcome stems back to the plant’s root system. During the flowering season, trimming spent flower stalks helps keep the garden looking tidy. Every few years, in the spring, trim Mexican petunia clumps back to a few inches above the ground to revitalize them.
The spread of this plant can be controlled with specific pruning methods. Cut off any spent Mexican petunia blooms before they set seed and pluck away any stems that have fallen to the ground and become rooted in the soil.
From Cuttings
You can increase the number of plants in your yard, for instance, by taking cuttings in the spring.
Cut a healthy-looking stem four to six inches from the end, just below a node, with a clean, sharp blade. Remove the bloom and any leaves that are close to the stem’s base.
Perlite and peat moss should be prepared in a clean four-inch pot and moistened. With a pencil, dig a two-inch-deep hole in the potting soil.
Place the cutting into the hole you produced in the potting soil after dipping the cut end of it in a powdered rooting hormone.
Keep your potted cuttings moist and in bright, indirect light. You can transplant them outside once the roots have taken.
Division
To divide this plant, aerate the surrounding soil and then excavate the desired clump.
Lift the clump out, then use a shovel to cut the plant’s crown into many pieces.
Put your transplants into holes that are twice as broad and the same depth as the root balls of your clumps. In the holes, distribute the roots widely.
When the roots are well-established, keep watering them well for many weeks after covering them with earth and watering them well.
How may purple Mexican petunias be gotten rid of?
You may be interested in learning how to get rid of Mexican petunias if you reside in one of the nine states where Ruellia is most prevalent. Mexican petunia removal is actually a long-term undertaking that calls for careful monitoring of the garden or lawn where they have taken over. You must be fully committed to this war because the Mexican petunia’s seeds can continue to grow for years after the mature plants have died off.
Mexican petunia can be pulled, but if you don’t get the full root or miss a sprout, you’ll have to go through the whole process again soon. The best option is to use glyphosate to destroy the plants from the ground up by spraying it on the foliage. After the initial application, regrowth is to be anticipated, so be ready to spray once again whenever you see the plants putting forth new leaves.
You can prune the plants by hand if your Mexican petunias are in the lawn or another delicate area where applying herbicides might not be the best idea. Dispose of the vegetation carefully to prevent any danger of it growing back. Since you’ll only be removing the top layer of the plant, you’ll need to cut it again each time it begins to leaf out in order to make the plant burn up its energy reserves and exhaust its food supply.
Mexican petunias spread how quickly?
Mexican petunia, also known as desert petunia, quickly takes root when you start with a seedling or young plant that has been produced in a nursery. Typically, clusters of 3 foot tall, sturdy, semi-woody stalks bearing lovely leaves and blooming within a month or two are produced. The plant’s first season typically features purple flowers that bloom from mid-spring until late-fall. You can promote fast, healthy growth and an abundance of flowers by siting the plant in full sun, which stimulates it to produce flower buds and also helps leaves stay a rich, dark green.
How much height can a Mexican petunia reach?
On the dreary, rainless month of July, when a plant is flowering ferociously in a strip of compacted ground between a parking lot and a concrete wall, you know it’s a hardy customer. That’s just one of the many reasons why Mexican petunias are so beloved.
Mexican petunia is native to the region south of the border, as its name suggests. (No, I’m not referring to that cheesy tourist attraction on the border of North and South Carolina where Pedro sells sombreros the size of beach umbrellas.) Although Mexican petunia is not a true petunia, its blossom resembles one. Ruellia brittoniana is the official botanical name, although you’ll also hear it referred to as R. malacosperma and R. tweediana. Some people claim that these are various plants, while others claim that they are all the same plant. Who the h*** cares, says Grumpy? Really, though. We’re all quite busy.
Mexican petunia grows 3 to 4 feet tall, with elegant, purplish stems, and slender, lance-shaped leaves. It is cold-hardy in UDSA Zone 7 and southward. From early summer to the end of the season, butterflies and hummingbirds like the showy blue or purple blossoms. How flamboyant are they? Well, you know even non-gardeners find Mexican petunias attractive when you see pots upon pots of them blooming in front of Home Depot and Lowe’s.
First the positive. In full to partial sun, Mexican petunia is remarkably simple to grow. One of the few perennials Grumpy is aware of that thrives in both wet and dry soil is this one. I frequently observe it flourishing in areas with no attention, such as traffic islands, gas station landscaping, and areas between sidewalks and curbs. And as I just said, hummers and butterflies want it. Although each flower only lasts for one day, new flowers are constantly opening.
Then the bad. This plant can become out of control because it has survived. It grows thick clusters through spreading roots that are difficult to eradicate. And the seeds from its exploding seed capsules are dispersed everywhere. It may become invasive in humid environments and unmanaged regions. Although I don’t think it compares favorably to kudzu, popcorn trees, privet, and water hyacinth, the state of Florida does consider it to be such.
So, do you still need to plant it? Yes, provided you only plant non-invasive species. Fortunately, Grumpy is aware of a few that are currently offered by mail-order nurseries and garden retailers.
The first is right here. It’s a dwarf by the name of Katie. It reaches a height of 10 inches and a width of 12 inches. It produces few seeds and does not spread quickly. From June until frost, huge blue-purple blooms are in bloom. This one works well when used in a mass as a ground cover. The mail-order supplier Niche Gardens is reliable.
‘Purple Showers’ is a different Mexican petunia to take into account. It resembles the plant in the top photo a lot, but it has larger, deep purple blossoms. Purple Showers, a plant created by the University of Florida, is sterile and does not produce seed. Plant it in dry soil instead since it can still spread through roots. This one is available for order from Avant Gardens. Additionally, big-box stores sell it.
Your third option is to go native and plant the sweet little Carolina wild petunia (R. caroliniensis), which is native to the Midwest and South and is depicted above in my garden. It just gets to be a foot tall and blooms intermittently all summer. Some of it will disperse by seed, but not enough to be bothersome. It is also equally as resilient as Mexican petunia. Jean in Tennessee gave me hers, and despite her fervent support for the Volunteers (oh, the humiliation! ), she’s a beautiful person. Woodlanders will take your order. It thrives in the sun and light shade for me and is more tolerant of the winter than its Mexican cousin.
I am aware that this summer has not been kind to tomato growers, but Grumpy still has faith in you! Enter Grumpy’s Big Fat Tomato Contest by August 31 to avoid missing out. Awards will be given for: