Archive | February 6, 2014

2014 is the Year to Party with the Petunia

Blogged with permission of National Garden Bureau.

2014 is the Year to Party With a Petunia!


Every year, National Garden Bureau names one edible, one annual and one perennial as featured crops for a year. 2014 is the Year of the Petunia. NGB, along with our members, provide these tips about an annual flower enjoyed by many. Over 100 petunia images from our members can be found on the NGB website or in a Year of the Petunia presentation on Slideshare.
What’s not to like about petunias? These incredibly versatile plants come in an abundance of sensationally bold colors, are widely adaptable, vigorous, self-reliant and largely pest and disease free. They are low maintenance and drought tolerant, widely available, are a great value, sport a variety of forms and colors, and some even exhibit a light, sweet fragrance. Additionally, these fail-proof, tried-and-true beauties are easy to grow, bloom ceaselessly from late spring to fall and settle in comfortably whether planted in gardens, trailing from containers or spilling out of hanging baskets. They’re beautiful, desirable and completely irresistible to butterflies, hummingbirds and gardeners alike. Thanks to new, fashionable shapes and attractively colored blossoms, the petunia is still one of the most popular summer flowers. In short, the perfect go-to gardening friend for sunny places.

History – Then

Though generally treated as annuals by most gardeners, technically they are tender perennials and are members of the potato family of plants. Today’s feisty hybrids are the descendants of two lanky, tiny-flowered South American species: the buff-white flowered Petunia axillaries and the night-fragrant, lavender to purple-flowered Petunia violacea. First discovered in South America in the late 1700’s these wild varieties quickly captured the imaginations of European breeders who began crossing them in search of the perfect petunia – a plant with large beautiful flowers in a variety of colors.

Following the end of World War II, the transformation in the quality of petunias came with the development of the F1 hybrids. Weddle, one of the founders of PanAmerican Seed Company, won an AAS award in 1949 for the first F1 single-flowered multiflora, ‘Silver Medal’ and in 1952 crossing a grandiflora with a multiflora producing a F1 vigorous grandiflora hybrid ‘Ballerina.’

History – Now

A whole new world opened for petunias and their breeders with the development of the F1 hybrids. This made it possible to regulate their growth from the open, floppy forms to a bushier type with better weather resistance, an increasing range of colors and color-combinations and a far superior ability to weather the rigors of summer.

As is quite obvious, in recent years the world of petunias has become a complex world, for there are – literally – hundreds of named petunia varieties. But a bit of advice for pairing the right petunia with your gardening needs can be summarized, in part, in the following manner.

Grandiflora: large-flowered blossoms (4-5”) consisting of both single- and double-flowering cultivars form mounds of colorful solid, striped, deeply veined, variegated or edged in a contrasting shade called picotee. Grandifloras prefer a cool, dry sunny environment in protected areas and dislike hot, wet or windy conditions, and work well in both containers and beds.

Multiflora: compact plants with smaller (1.5-2”) flowers than the grandifloras; however, they bloom prolifically and freely all season long. These plants have single or double flowers and are available in a rainbow of colors, often with contrasting centers or stripes. Bred primarily for the wetter climates these petunias perform admirably in adverse weather conditions especially during very hot or very wet spells.

Milliflora: petite, (1-1½”) blossoms produced with wild abundance that cover the plant with beautiful vibrant colors. Perfectly suited to containers, hanging baskets, miniature gardens and as edging plants, these delicate beauties bloom earlier, do not stretch, add fullness and contrast of size and color when combined with larger blooming plants.

Spreading: low-growing plants only (4-6”) in height that can spread up to 5 feet across. These are fast growing plants with excellent heat and drought tolerance, require very little maintenance, and make excellent flowering ground covers. Their greatest popularity lies in their wild profusion of blooms that tumble out of hanging baskets, window-boxes and tall containers from late spring well into late fall in milder and warmer regions.

Hedgiflora – one segment of Spreading: have growth habits based on how closely the plants are spaced in the garden. Grown close together, they form a dense, mounded hedge from 16 to 22 inches tall. Grown in restricted space with some support, they act like vines growing upward an extra 2 to 3 feet. But when given plenty of space to roam, they make a floriferous groundcover spreading 2½ to 3 feet.

Floribunda: an improved multiflora petunia bred to have larger single- and double-flowered varieties that bloom earlier while producing an abundance of flowers. Like the grandifloras, they flower earlier, yet tolerate both hot and wet periods, perking up quickly after every rain shower. Floribundas are a fantastic selection for mass plantings in the landscape, and for container plantings in pots and hanging baskets.

Petchoa (SuperCal): a combination of the best characteristics of the petunia and calibrachoa plants. The Petchoa ‘SuperCal’ plants deliver unique colors, sturdy blossoms and non-sticky foliage to overflowing hanging baskets.

For growing and planting instructions, read the full Petunia Fact Sheet here.

Petunia Maintenance
Petunias don’t require a lot of care, but they do benefit from some attention. During dry weather, a deep watering once a week should be sufficient for petunias in beds and borders. Plants in containers, hanging baskets and window boxes will need to be watered when the soil surface becomes dry – on extremely hot, sunny days that could be daily – and fertilized every couple of weeks with a dilute fertilizer solution.

Always check the cultural tags that come with the purchase of your plants. Many of the new cultivars are bred for compactness or mounding and require no pinching back or deadheading. Your cultural tags will give you this information. But as a general rule, to encourage additional blooms and improve plant appearance, remove the spent flowers on grandiflora and double petunias. This not only keeps plants blooming longer, it also keeps plants looking fresh, healthy and well groomed. The smaller flowering types, such as the milliflora and spreading petunias are self-cleaning and don’t require deadheading. And although it isn’t practical to deadhead sweeping stands of petunias in the garden, it’s advisable to do so for plants in containers. After pruning, fertilize and water the plants to promote new growth.

Today’s newer cultivars are pretty much disease-resistant, but as with all plants, a few problems can develop and you will want to deal with them as soon as possible.
Newly germinated seedlings can fall prey to damping off, a fungus that attacks at the soil level and is irreversible. The young seedlings will wilt and die almost overnight. Avoid damping off by using a commercially available soilless mix and use only clean, sterilized containers for starting seeds.

Young plants are susceptible to Botrytis, a fungus that is also soil-borne and spreads quickly from an infected plant to a healthy one. It thrives in cool, moist conditions, forming a powdery mold on stems, leaves and flowers. Watering only early in the morning, avoiding overhead irrigation and keeping plants spaced for good air circulation are all good ways to avoid these problems.
Petunias are also susceptible to various viruses which can leave foliage stunted and deformed with discolored and deformed flowers. The safest control is to remove and destroy diseased plants and keep aphids and other insects which can transmit the disease off the plants by hosing the plant with a strong blast of water.

Petunias in the landscape can be bothered by different pests: flea beetles which eat holes in the leaves of the plants and the small, green budworm caterpillar which attacks plants in late June and July and feeds on the flower buds. Usually, you won’t see the actual caterpillar, but you should notice small black droppings and tiny holes in leaves. If you have a major infestation, apply Bt (Bacillus thuringiensis).

Petunia plants may look limp and scraggly after a hard rain; however, the newer cultivars usually perk up within hours. Most petunias have naturally sticky leaves and stems (some of the newer cultivars have this trait bred out of them), so don’t panic and think this condition is disease or pest related.

The Much Requested Garden Glossary

Over the years as I have written this blog, I have had a number of people write a comment on an article that pretty much follows the same summation: “Hi, please don’t put this up on your blog, but what does ______ mean. I have never heard of that one.”  Some of the words are scientific names that are in Latin, while others are maybe a little more ‘high end’ gardening terms that a beginner may not know.

Either way, I thought it would be a great time to compile a number of the gardening terms I have been asked to define into one nice little article.  If asked again, I can get a link click out of it. ;o)


Acidic Soil     

A soil that has a pH below 7, typical of clay soils. Azaleas, camellias, dogwoods and roses like acidic soils.

Alkaline Soil     

A soil that has a pH of 7 or higher.

Annual Plant     

A plant living one year or less, usually planted in the spring after the last frost. During this time, the plant grows, blooms, produces seeds, and dies.

Balled & Burlapped     

The roots of the plant have soil attached and are held in place with burlap or some other material.

Bare Root     

The roots of the plant are bare, with no soil.


Of two seasons duration, from germination to maturity and death, usually developing vegetative growth the first year and flowering, fruiting, and dying the second year.  Biennials need exposure to winter temperatures to trigger flowering or fruit production the second year.


A resting stage of a plant that is usually formed underground and consists of a short stem base bearing one or more buds enclosed in fleshy leaves and buds (tulip, daffodil, etc).


A rounded, thick modified underground stem base bearing membranous or scaly leaves and buds (gladiolus, crocus, etc).


The base of the plant, where the stem and root meet.


A cultivated variety or strain that originated and has persisted under human cultivation.


Removing the dead blossoms.  If a plant is termed “self cleaning,” the blossoms fall off on their own.  Deadheading usually extends the blooming season.


A plant that loses its leaves seasonally, usually in the fall.


The growth of a plant stops at a certain height (usually in reference to tomatoes).


A period in the life cycle of a plant where it is “asleep” and not actively growing.  Dormancy is brought about by cool temperatures and shorter day length.


A plant that stays green year-round.


Bearing flowers/blooming freely.


The sprouting of a seed and the commencement of growth.  Also used to describe the starting of plants from seeds.

Grafted Plant     

The top (desirable) part of the plant is grafted onto rootstock, usually of a hardier or less rare plant.

Heirloom Seed     

Mostly open-pollinated seed that have been planted and passed down for generations. Most lack disease resistance.


A plant that dies back to the ground in winter and returns again in the spring.


A chemical used to destroy undesirable plants and vegetation.

Hybrid Seed     

The result of cross-pollination of parents that differ in size, color, taste, or other traits.  Seeds from hybrid plants cannot be saved and used again, as they will revert back to one of the parents.


The plant continues growing until pinched or killed by frost (opposite of determinate). These plants usually require staking.

Organic Seed     

A seed that has been grown and harvested without being exposed to any inorganic chemicals, fertilizers, hormones, etc.Pelleted Seed     

Small seed, such as petunias or pentas, that have been coated with an inert material such as clay to make them easier to handle.

A plant that lives for three or more seasons. Perennials may not bloom the first season planted, especially ones that are shipped bareroot.


A somewhat elongated, usually horizontal subterranean plant stem that is often thickened by deposits of reserved food material that produces shoots above and below the roots (bearded iris).


Root system of a more common or hardy variety that is used to graft a more desirable variety onto, usually roses and/or standard forms.


Plants that do not require pollen from another plant in order to produce fruit.


A plant that drops its leaves in cold areas but keeps at least some of them in milder zones (typically zones 7~11).


A shrub or herb grown with an erect main stem so that it forms or resembles a tree.


Undesirable growth coming from the rootstock of a grafted plant.

Treated Seed     

Seed that have been treated with an insecticide or fungicide to aid in preventing soil insects or disease from destroying the seed prior to germination.


A short, fleshy, usually underground stem bearing minute scaly leaves, each of which bears a bud in its axil and is potentially able to produce a new plant (iris potato, caladium, tuberose begonia).


If there is a term that is missing from this list that you would like to know, leave a comment and I will add it! Thanks for reading!


© Mertie Mae Botanics LLC and Horticulture Talk!, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Mertie Mae Botanics LLC and Horticulture Talk! with appropriate and specific direction to the original content.