Hydrangea macrophylla
This familiar image of a hydrangea is what many people think of over the years from their childhood. The soft pastel pink or blue flowers are commonly seen in gracing landscapes. This is the hydrangea that is planted most often. They are also the hardest to grow successfully. They are usually done blooming by mid-summer.
In Missouri, we have two highly successful hydrangea to be considered: Panicle and Oakleaf
Panicle hydrangea (botanically as Hydrangea paniculata)
Panicle hydrangea (Grandiflora commonly referred to as PeeGee)
The panicle hydrangea all flower white and have some variations. They start out white and may fade to very light shades of pink or lime green, depending on the variety. Flowering begins mid-July and peak in early August with color lasting well into the fall. In the hottest, driest part of summer, the flowers are a bright spot.
Pruning is as simple as cutting the plant back to the ground each spring but some varieties will grow 6 to 8 feet if allowed to grow. They do best in evenly moist soil and will tolerate our heavy clay soils if allowed to drain. Organic matter in the soil produces the happiest and most vigorous plants. The panicle hydrangeas are more drought tolerant than other hydrangeas. They put on their best floral display in either full or almost full sun but can be grown in shady locations which will result in smaller flowers. It does provide some color when there is little other options for summer blooming in shady areas.
A plant recently growing in popularity is commonly referred to as PeeGee. The flowers produced are so large and heavy, they can droop. It can be sold as a standard or as a tree form. As a small tree, it has rounded to umbrella shape and droops with flowers.
Other varieties of panicle hydrangeas include a great older variety, Tardiva, which is credited with bringing this plant into the gardening mainstream. Limelight starts out white and turns a bright lime green shade which lasts for months. Other favorites include Little Lamb and Little Lime which grow best in compact areas topping out at 3 to 5 feet height. Some varieties attempt to bring more color with shades of very light pink.
Oakleaf Hydrangeas - spring
Oakleaf hydrangeas - summer to fall
Oakleaf hydrangeas - fall
Oakleaf hydrangea (botanically as Hydragea quercifolia) is a tried and true plant that deserves a spot in all area landscapes. It is one of those rare four season plants that is a spectacular year-round show. It starts in spring with beautiful white flower clusters that cover the plant and lasts two to four weeks, a long time for flowering shrubs. As the flower's peak display passes, the faded flowers still have character transforming from pure white to pink hues.
Eventually, the clusters dry to a nice creamy bronze that creates interest for the remaining summer and into fall. The large green, leathery textured leaves are deeply lobed giving them more the look of an oak for the name oakleaf hydrangea. The leaf color in the fall changes from the deep green to various shades of wine-red to purple and rich burgundy for weeks. The colors are clear and bold especially with sun back lights.
Another feature of this plant arrives in the winter. The leaves drop revealing the inner-beauty of young branches. They are a nice brownish color and as the stems age, the bark begins to exfoliate or peal, developing a rich cinnamon-brown papery appearance that is most showy when snow blankets the ground.
The Oakleaf hydrangea is adaptable but prefers morning sun with light shade in the afternoon. It will tolerate more sun but will need to be kept evenly moist for best growth. It will tolerate some shade and still flower. It can be quite drought tolerant once established but is best with supplemental moisture during dry spells. If situated correctly in the landscape, little pruning is required. It flowers on old wood so don't prune until after it blooms.
Some of the varieties include Alice (largest), Snowflake (double blossoms), Snow Queen (more sun tolerant), Sikes Dwarf (less than 4 feet height), Pee Wee ( smallest at 2-3 feet height), Vaughn's Lillie (largest flower head).
In Missouri, we have two highly successful Hibiscus to consider: Hibiscus syriacus (common name Rose-of-Sharon) and Hibiscus moscheutos.
The tropical sort, the Chinese Hibiscus (Hibiscus rosa-sinensis) with glossy leaves and clear, brilliant colors is not hardy and cannot survive winter out of doors here in Missouri. This what you would see grown indoors and are commonly obtained from a florist shop.
Hibiscus syriacus (common name: Rose-of Sharon)
Hibiscus syriacus (common name: Rose-of-Sharon)
Most commonly sold in local landscape nurseries are the woody shrub or small tree labeled hibiscus syriacus. It is commonly called Rose-of-Sharon. They are of irregular and varying shapes, bearing smaller blossoms of same colors.
Hibiscus moscheutos
Hibiscus moscheutos
The common bushy plant that grow with pithy stems to heights and widths of 3 to 5 feet are called the hibiscus moscheutos. They are perfectly tolerant of winter. Only 20 years ago, they were mainly white, pink, and red-flowered varieties. Due to the diligence of plant breeders and curious folks who sow natural seeds, many varieties have now appeared. The flowers can now be found in red, pink, white, purplish, cranberry, and even pale yellow. No true blues yet. There are maple-like leaves and those stained with purple, cranberry or variegated colors.
This hardy hibiscus descended, or was improved, from the white to pale pink-flowered Swamp Mallow that is native to wetlands from the deep South to as far north as our Lake Stockton and St. Louis in Missouri. A popular variant is the Texas Star Hibiscus which can grow as tall as 6 feet, with upright canes topped with star-shaped flowers, mostly in shades of red to pink or white.
There are many choices available if the gardener or property owner wants some additional Flower Power after all the lovely flowers of spring and summer fade away. Consider these Flowering Shrubs and you will see some end of season color that will extend the prime growing season in our area.
Hibiscus information taken from Grounds for Gardening (August 7, 2013) by John Lower, retired University of Missouri Extension horticulturist.
Hydrangea information taken from Kansas City Star (August 7, 2013) by Dennis Patton, Horticulture Agent Johnson County K-State, Research and Extension.
Posted 8/24/2013
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