Ruellia humilis

wild petunia
Light Requirements
sun, part-sun, part-shade
Soil Moisture
dry, moist
Soil Description
average, poor, loam, clay, sand, gravel/rock
Bloom Time
June, July, August, September
Bloom Color
lilac, lavender, blue
Hardiness Zone
4, 5, 6, 7, 8, 9
Additional Tags
attracts butterflies, colonizing, cottage garden plant, deer resistant, drought tolerant, naturalizing, rock garden plant
Ruellia humilis is a compact, profusely-blooming perennial that can reach up to 2', although it typically grows to a height of 1'. The leaves are oblong, up to 2" long, and covered top and bottom with fine hairs that give the foliage a silvery cast. The flowers are trumpet-shaped and petunia-like, up to 2 1/2" long, and range in color from lavender to lilac. They are produced in the upper leaf axils, forming open clusters.
Wild petunia is very versatile and easy to grow. It is intolerant of wet feet and full shade, but other than that, it will grow under just about any conditions. It is a profuse bloomer, beginning in early summer and going strong through the hot, dry summer months. When grown in rich, moist soil, it can be bullied by taller and more aggressive species, so it is best planted en masse in the front of the flower bed. It spreads readily by seed (the pods burst open when ripe, projecting their seeds far and wide), particularly in disturbed areas, but can be controlled by deadheading. This propensity to spread, and low-growing habit, can be useful to fill in gaps in the garden and when establishing a low meadow. On the shadier side of its tolerance, it pairs well with Aquilegia canadensis and Polemonium reptans, and will extend the blooming interest of the planting through the end of summer. In full sun, it pairs well with Eragrostis spectabilis, creating a subtle contrast with the grass. Zones 4-9
Additional Notes

The genus Ruellia was named by Carl Linnaeus in honor of French botanist, and physician to King Francis I, Jean Ruel (1474 - 1537). Due to typographical interpretations, misidentification, and a yearning to Latinize names back in the day, he is also known as Jean Ruelle, Jean de la Ruelle, and Ioannes Ruellius (people’s names can get messy too).

The specific epithet humilis, is a Latin adjective meaning low-growing, and is the root for commonly used English words such as humble and humiliate.

The common name, wild petunia, is somewhat of a misnomer. Although the flowers are similar in appearance to those of true petunias, they come from two distinct families. Ruellia humilis is a member of the Acanthus family, whose best-known member (unfortunately) within gardening circles is Acanthus mollis (bear’s breeches), a species indigenous to southern Europe and northern Africa and now considered invasive in some areas of the US. True petunias are in the Petunia genus and are members of the Nightshade family, which includes tomatoes.

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Pricing & Availability

To view our Pricing and Availability, you will need to enter your shipping destination zip code.

You can also do so on any species page.


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Pricing & Availability


Taylor Creek Restoration Nurseries , WI

32-count plugs, full flat (32 plugs)

Only 15 left

10% OFF orders of 5 or more flats of any species from Taylor Creek Restoration Nursery.

20% OFF orders of 10 or more flats of any species from Taylor Creek Restoration Nursery.

See all products that qualify from Taylor Creek Restoration Nursery.


Spring 2021 advance ordering is now in effect. Orders placed now can ship as early as the week of April 5th 2021.

Would you like your plants to be shipped later? You may do so in the shopping cart.

Plants shipping from this nursery the first week of April might still be dormant but perfectly viable. If that’s a concern, please select a later shipping week during checkout.


North Creek Nurseries , PA

50-count deep plugs, full flat (50 plugs)

Only 29 left

10% OFF orders of 5 or more flats of any species from North Creek Nurseries.

20% OFF orders of 10 or more flats of any species from North Creek Nurseries.

See all products that qualify from North Creek Nurseries.

Spring 2021 advance ordering is now in effect. Orders placed now can ship as early as the week of April 5th 2021.

Would you like your plants to be shipped later? You may do so in the shopping cart.

If you wish to have plants delivered before the week of April 5th, please check with us BEFORE placing your order so that we can verify that your requirements can be met.



Taylor Creek Restoration Nurseries , WI

Seed packet

Any combination of seed packets and 4 oz mixes:

Add $5 for shipping orders of up to $100.
Add $10 for shipping orders of $100 to $200, etc.

Seed orders placed by 12 pm ET Wednesday will ship the following week. No exceptions please.

This packet will contain about 100 seeds.
Fall - Winter: Sow directly outdoors
Spring - Summer: 60 day cold moist stratification

For more planting guidelines, refer to the information in the "Shipping & Planting" tab above.


50-Count Deep Plugs

5" Deep Plug

Plugs refer to small containers, typically attached to one another to form trays, and are used in the early development stage of growing out plants.

This size plug is 2” x 2” across, and 5” deep. This allows for a large plant - up to 16” tall depending on the species and time of year - with a well established mature, deep root system.

32-Count Deep Plugs

32-count plug

Our 32-count plugs are typically the preferred size for plants that are shallow-rooted. The additional width of these plugs allows for horizontal growth of the roots, which benefits many species of ferns and sedges.

Each individual plug measures 2 ½” x 2 ½” across by 3” deep.

These plugs are landscape-ready, but also offer a head start should you be interested in potting them up.

Seed Packet

Seed packet

Depending on the species, our seed packets contain between 15 to 900 seeds. The approximate seed count is listed in the "Pricing and Availability" tab on each species page.

Seeds can be an economical way of propagating your own native plants.


Recorded County Distribution: USDA data

More Information

Native To

More Information

Legal Status

Endangered MD, PA, WI
Threatened MI, NC

Wetland Status

Atlantic and Gulf Coastal Plain FACU
Eastern Mountains and Piedmont FACU
Great Plains FAC
Midwest FACU
Northcentral and Northeast FACU

Interpreting Wetland Status






Obligate Wetland


Almost always occur in wetlands


Facultative Wetland


Usually occur in wetlands, but may occur in non-wetlands




Occur in wetlands and non-wetlands


Facultative Upland


Usually occur in non-wetlands, but may occur in wetlands


Obligate Upland


Almost never occur in wetlands


Kingdom PlantaePlants
Subkingdom TracheobiontaVascular plants
Superdivision SpermatophytaSeed plants
Division MagnoliophytaFlowering plants
Class MagnoliopsidaDicotyledons
Subclass Asteridae
Order Scrophulariales
Family AcanthaceaeAcanthus family
Genus Ruelliawild petunia
Species Ruellia humiliswild petunia


fringed wild petunia, hairy wild-petunia, hairy ruellia, low wild-petunia, fringed-leaved petunia, prairie petunia, low ruellia


Ruellia ciliosa var. longiflora

Ruellia humilis var. calvescens

Ruellia humilis var. depauperata

Ruellia humilis var. expansa

Ruellia humilis var. frondosa

Ruellia humilis var. longiflora



Sizes info


Shipping is free on all plants orders!

Your plants will ship using each grower’s preferred method: FedEx Ground, UPS Ground, or Spee-Dee Ground (in select midwestern states).

Our growers ship orders Monday through Wednesday. The farther you plants need to travel, the earlier in the week they will ship. The goal is to have all plants delivered by the end of the week.

Shipping plugs:

Plugs are shipped in full flats, sometimes also referred to as trays. Multiple flats can be shipped in a single box. The flats are wrapped in netting or craft paper to secure the plants, and spacers are used between flats to keep the plants from being crushed.

When you unpack your plugs, the plants will have been somewhat flattened by the netting or craft paper. They will straighten out within a couple of days. You may also gently “fluff” them a bit to speed up the process. In some cases, your plants might have been cut back before packing, if the grower deemed them to have become too tall for safe packaging. Don’t worry, though, these guys know what they’re doing and would not compromise the health of the plants. They’ll fill back in in no time.

After receiving your plants’ journey in a dark box, it will be important to acclimate them to sunlight again. Over a couple of days, you should gradually move them into their preferred light exposure, and water them as per their requirement.

Although we always recommend putting your plants in the ground as soon as possible, they can stay healthy in the flats for a considerable amount of time. The key is to respect their growing requirements: if the species requires full sun, do not store them in the shade. If it is best adapted to dry soil, do not over-water.


Planting plugs:

We consider plugs ready to ship when the plants’ roots have filled the entire liner cell and the plants can easily be pulled out. In some cases you will have to go about it gently, wiggling the plant by the crown, and possibly squeezing the bottom of the liner to compress the growing medium and release the roots. Other times, the plants will appear to be root bound. They are not in the traditional sense. The plants are healthy but they have used up all the growing medium available to them. Plugs are at an aggressive stage of growth. As soon as planted the roots will immediately expand into your native soil. They establish faster than plants in larger containers, because they don’t have the luxury of a lot of growing media that can inhibit the roots from venturing outside of their comfort zone.

We are not going to address area preparation because the process can be complex and is always site-specific. However, as a rule, we recommend disturbing the soil as little as possible, and we do not recommend amending the soil. If you chose the right plant for the right conditions they will thrive. Any disturbance and amendments will only encourage weeds to emerge that never had a chance to do so before.

Installing plugs cannot be easier: dig a hole large enough for the roots to fit snugly inside, then water them in to eliminate air gaps. We recommend using a soil knife, sometimes referred to as hori hori, or a drill-adapted auger if it’s a large installation. If you use an auger, you will need a powerful drill. Depending on the size of the project and the type of soil, the process can be beyond what an average drill will bear. Mulching is recommended after installation to help keep weeds down while the plants establish. Be sure to keep it away from the crown of the plants. For large projects, you may want to mulch the area before planting, rather than tiptoeing through it after the fact. As a side note: if you are installing plugs in the fall, you might want to plant them so that the crown is about ¾” lower than the surrounding soil. The winter’s freeze/thaw cycles can push plugs out if the roots did not have enough time to establish and anchor them in.


Starting and planting seed:

Direct sowing:

For most forbs - also referenced as flowering perennials - the best time to sow is during fall and winter to expose seeds to the natural cycles of alternating cold, moist and warmer weather that they have evolved to require in order to germinate. There are of course some exceptions, and some species will germinate under warm conditions regardless of having first been exposed to a cold period. Most grasses fall under this category. There are also species that will require a couple of years of cycling temperatures in order to germinate, so it is important to understand each species’ requirements and manage one’s expectations accordingly.

Soil preparation:

Like any type of garden, a well-prepared soil makes the difference. Remove any large debris. Kill and remove any grass sod. Till and rake the soil until an even surface is achieved. Starting from seed is the most cost effective way to start your native planting; however, it requires time and patience. Most species we carry are perennials, meaning they will come back each spring for many years. As perennials, the plants will grow slowly and may take several years to mature and flower.


Planting seeds:

Planting these seeds is very similar to planting other types of seeds: small seeds are planted very shallow and large seeds are planted deeper. A good rule of thumb is to plant the seed the same depth as the seed’s thickness. For example, a 1/16” thick seed is planted 1/16” deep. A light straw mulch is recommended for late fall seedings. There are also some seeds that, either due to their small size or light requirements to germinate, should only be surface sown and kept clear of any coverings.

Sowing seed can also be a good way to add diversity to an existing planting. Should that be your application, soil preparation is not necessary because you will be mimicking the process by which plants naturally spread in established environments. To improve germination rates, winter sowing is very effective especially right before a snow event. The snow will hide the seeds from foraging birds and mammals, provide the steady moisture needed to trigger germination, and will help work the seeds down to the soil as it melts.

Once plants are established they will require minimal maintenance. Remove any large weeds, especially if they flower and set seed. If weeds become a problem in seedings you can mow during the first two years to a height of 10-12 inches. This will benefit your perennial plants by providing more sunshine.


Starting your seeds indoors:

If you want to have more control over the germination process and planting - or if you want to start your seed in spring or summer before they are exposed to freeze/thaw cycles - you will want to mimic natural conditions by using a process known as cold/moist stratification:

There are several methods that can be used to stratify seed. For large quantities, the recommended method is to mix the seed into a moist, sterile medium such as sand, perlite, vermiculite, or a combination of the 3, and then refrigerate as required. For smaller quantities, spreading the seeds evenly between moist sheets of paper towels and refrigerating them in a resealable plastic bag will do just fine. You should check regularly to verify that the medium, or paper towels, has not dried out. You also need to check for any signs of germination that might occur before the recommended stratification period has elapsed. Should that occur, or if you have met the recommended stratification period, you should remove the seeds and plant them immediately in your preferred potting medium. Use the previously mentioned guidelines for determining seed depth.

Some seeds have especially hard protective coatings. In nature, those get broken down by soil abrasion or by passing through an animal or bird’s digestive tract. In addition to stratification, those seeds will require scarification to improve germination rates. Several methods can be used to achieve this. Gently rubbing the seeds between two sheets of fine sandpaper is one of them. Another method is to mimic exposure to digestive enzymes and to soak the seeds for 24 hours in some diluted tea.

If you do start your seed indoors, we recommend timing the process so that germination will occur after the last chance of frost. That way you can move your seedlings outside without having to manage appropriate indoor light exposures.