Species and Varieties
Are you wondering what type of flowers and ornamentals to grow? Penn State Extension has extensive resources you can use to help you decide. Here you’ll find information on species and varieties of ornamentals and floriculture. They include poinsettias, violets, hydrangeas, viburnum, marigold, pansy, lilac, mountain ash, irises, lilies, narcissus, impatiens, holly, pothos, hostas, gloxinia, and many more.
How to Choose What Flowers to Plant
There are many different flowers and ornamentals to choose from. Which ones will be best to grow depends on several factors. You can see some of the newest annual and perennial flowers offered in the spring to garden centers and landscape clients at the Penn State Extension Flower Trial Field Day.
If you’re considering growing cut flowers, some bedding plants might be the easiest option. Choose varieties that are specifically bred for cutting and you'll increase your chances of success. Some plants can be poisonous to horses, dogs, and cats, so bear this in mind when choosing plants for your garden. Certain plants are also more prone to disease, which means they have to be monitored on a regular basis. This might not be ideal for people who want low-maintenance plants.
A popular choice for many gardeners is Pennsylvania native herbaceous (nonwoody) perennial plants as they provide year-round interest to any landscape.
The best results will be achieved if you choose plants that thrive best in certain conditions. Here are some examples:
- Sun to part sun/dry to moist soil: Tulip tree, wild plum, sweet-fern, fragrant and staghorn sumac
- Sun to part sun/wet to moist soil: Fringe tree, black gum, buttonbush, swamp azalea
- Shade to part shade/dry to moist soil: Mapleleaf viburnum, wild columbine, northern sea oats, wreath goldenrod
- Heat and drought-tolerant plants: Goldenrain tree, lilac, pot marigold, butterfly weed
Some of the most popular flowers and ornamentals grown in Pennsylvania include:
- Hardy geraniums: There is an ever-increasing array of excellent hardy species and cultivars that perform very well in most locations.
- Hydrangeas: Many species and cultivars of hydrangea flower from mid-July to August in colors ranging from white through to shades of pink and red. Hydrangea arborescens 'Annabelle' is a favorite in the landscape.
- Poinsettias: This popular Christmas gift is very sensitive to cold temperatures and drafts.
- Peony: It’s possible to create an exquisite and long-lasting display by planting different types of peonies.
- Clematis: Also called the ‘queen of vines’, its flowers add grace and elegance to a landscape.
- Orienpet lilies: These lilies combine the best characteristics of Oriental and trumpet lilies.
Choosing Woody, Deciduous, Evergreen, and Other Ornamentals
Shrubs are very popular with home gardeners because they can provide year-round interest to a landscape. Evergreen shrubs and trees, such as rhododendrons and azaleas, grow very well in Pennsylvania. Native evergreen plants include Christmas fern, seersucker sedge, and mountain laurel.
There are, however, some shrubs you should avoid. Certain shrubs may look very attractive and appear harmless but can be detrimental to local ecosystems. Japanese barberry, butterfly bush, privet, and burning bush are all very invasive species.
While it can be very tempting to stick with popular species and varieties, there are always alternatives for those who want to have something a little different. Juniper is a very common sight in landscapes across Pennsylvania, but the Russian cypress is an exciting alternative. Its cold hardiness makes it very suitable for the area. Hesse cotoneaster makes for an interesting alternative ground cover plant. Numerous boxwood varieties and hybrids are now available for those who prefer to stray from the traditional path.
Something to bear in mind when choosing woody, deciduous, evergreen, other ornamentals, and trees and shrubs is the aftercare and maintenance required. Penn State Extension offers online training courses for those working in the landscape industry as well as amateurs who want to increase their working tree knowledge.
- Articles
Goldenrod Diseases
Informational table showing disease name, symptoms, pathogen/cause, and management of goldenrod diseases. - Articles
Cutting Down Perennials in the Fall
Most of the perennials in the garden are finished blooming and it's time to throw in the towel for the growing season. - Articles
A Guide to Dividing Perennials
One of the gardener's most rewarding tasks is dividing perennials. Not only is it an easy way to acquire more plants, but it helps them stay vigorous and healthy. - Articles
Underused Woody Ornamentals: Halesia carolina
One of the early flowering small trees I anxiously await every spring is Halesia carolina, Carolina silverbell. - Articles
European Fruit Lecanium
The European fruit lecanium is a key soft scale insect pest of shade trees and other woody ornamental plants in Pennsylvania. - Workshops
Free
Fall Flower Trials Open House
When 09/25/2026Length 3 hoursExplore new plant varieties for fall sales through a guided tour of trial displays featuring annuals and perennials, seasonal merchandising ideas, and inspiration for fall offerings. - Articles
Gloxinia Diseases
Informational table showing disease name, symptoms, pathogen/cause, and management of Gloxinia diseases. - Articles
Gladiolus Diseases
Informational table showing disease name, symptoms, pathogen/cause, and management of Gladiolus diseases. - Articles
Gerbera Diseases
Informational table showing disease name, symptoms, pathogen/cause, and management of Gerbera diseases. - Articles
Gaillardia Diseases
Informational table showing disease name, symptoms, pathogen/cause, and management of Gaillardia diseases. - Articles
Boxelder Bug
The boxelder bug frequently becomes a nuisance pest around homes and buildings near plantings of the boxelder, Acer negundo. - Articles
Aphids on Ornamentals
Many species of aphids or plant lice occur on ornamental trees and shrubs in Pennsylvania. - Articles
Magnolia Scale
The magnolia scale is one of the largest scale insects in the United States. It feeds only on magnolia. - Articles
Eastern Spruce Gall Adelgid
The eastern spruce gall adelgid is a key pest of Norway spruce, Picea abies, in northeastern United States. - Articles
Oystershell Scale
The oystershell scale is a common armored scale insect that causes injury to shade trees and shrubs, most often lilac, ash, dogwood, maple, poplar, and willow. - Articles
Obscure Scale
The armored obscure scale is a key pest of oak in Pennsylvania, and can attack other woody host plants such as beech, dogwood, hickory, maple, and willow. - Articles
Spring Plants that are Poisonous to Horses, Dogs, and Barn Cats
Many ornamental plants can be harmful to horses, dogs and barn cats. - Articles
Care and Maintenance of Perennials
There is some basic care needed to keep your perennials in their best form and to come back year after year. - Articles
Nomenclature
Plants may be known by different common names, and one name may refer to various plants within several species. Use the scientific or botanical name to properly identify plant material. - Articles
Landscaping and Gardening Around Walnuts and Other Juglone Producing Plants
Walnuts and hickories produce the chemical juglone (5 hydroxy-1,4- napthoquinone), which is exuded from all parts of the plant. - Articles
Eastern Redbud: A Superb Tree for Almost Any Landscape
Eastern redbud (Cercis canadensis) is a small, graceful tree native to the eastern and central United States. - Articles
When to Prune Which Hydrangea Species
Hydrangeas are one of the most popular flowering shrubs for many reasons. - Articles
Tough and Beautiful is Hard to Beat
Parrotia persica, also known as Persian ironwood, is native to a relatively small region of northern Iran and Azerbaijan, near the southern edge of the Caspian Sea. - Articles
Lacebark Pine: Its Bark is Better Than its Bite
Lacebark pine, Pinus bungeana, is native to eastern and central China. - Articles
Heat and Drought Tolerant Plants
Sandy Feather, extension educator in Allegheny county, has prepared this list of trees, shrubs, annuals and perennials that don't just survive but will thrive in our long, hot summers.

























