Althea goes by the scientific name of Hibiscus syriacus. When most gardeners view the plants, they are reminded of the hibiscus family, to which this popular, Southern heritage plant belongs. These plants are also referred to as rose of Sharon.
Continuing the tropical theme for ornamental plants of the week in August is cassava, also called tapioca plant. This is a tropical, shrubby perennial we normally treat as an annual. But we can find this plant over-wintering in warmer locations south of Interstate 10 in Louisiana.
Ornamental peppers produce colorful fruit – which are actual peppers – in a wide range of sizes, forms and colors. Purple, orange, yellow, red, brown, blue and white are common. Multiple colors can appear on the same plant.
The industry standard in rudbeckia is the Goldsturm variety, which is widely available in Louisiana. Normally, this variety flowers twice during the year. A good bloom occurs in late spring through midsummer, and you can get some fall flowers, too. A new variety that was developed from Goldsturm is Early Bird Gold. It is a great landscape performer and was found by Dupont Nursery in Plaquemine, Louisiana, to be an earlier-blooming sport of Goldsturm.
Looking for some of the best of the multi-seasonal flowering azaleas? Look no further than the Encore azaleas – the “azalea that knows no season.” Encore azaleas were born and bred in Louisiana by horticulturist Buddy Lee, of Independence. With almost 30 varieties now in the trade, you can select Encore azaleas for dwarf, intermediate and taller growth habits.
Oaks are one of our most popular landscape trees. Almost everyone is familiar with the Southern live oak, but we have an abundance of other oak trees – largely deciduous – that are recommended for Louisiana. The willow oak (Quercus phellos) has been named a Louisiana Super Plant. Deciduous oaks – those that lose foliage in winter – common in Louisiana are water oak, shumard oak, Southern red oak and willow oak.
Redbuds are one of our more popular early spring-flowering small trees. The most common redbud species is the Eastern redbud – Cercis canadensis – the one we primarily plant in Louisiana. Other redbuds include forms that are native to Mexico, Texas and Oklahoma. Redbuds usually start flowering in mid-February in Louisiana and continue through late March.
Cool Wave Pansies: To enjoy pansies all season long, properly prepare the bed to allow for good internal drainage and aeration. Make sure soil pH is between 5.5-6.0. Add fresh, nutrient-rich, finished compost, which also is a great source of organic matter. For a traditional fertilizer approach, apply a slow-release fertilizer at planting. Most slow-release fertilizers for home use are three- to four-month formulations.
Peacock Kale – Ornamental Plant of the Week for January 5, 2015 The ornamental or flowering kales typically have feather-type leaves as compared to the rounded leaves of ornamental cabbage. The deeply serrated leaf edges add unique foliage texture to the cool-season landscape.
Nicotianas are good alternative cool-season bedding plants for south Louisiana. Nicotiana is flowering tobacco. Most for landscape use are “dwarf” in size but still reach heights of 24 inches. Nicotianas have less cold hardiness than some other cool-season flowers, however. So that needs to be considered. In south Louisiana, they should be able to withstand winter temperatures as long as plants are hardened off some before the first frosts and freezes.
Pericallis – Ornamental Plant of the Week for February 2, 2015- These are good plants for late-winter through late-spring flower color. Ideally, pericallis should be used as a decorative container plant. Pericallis are cold hardy to the upper 30s or low 40s. They’re not frost-tolerant and will need some protection if planted in a landscape before the last killing frost or freeze.
Plant spreading petunias 18 inches apart and clumping petunias 12 inches apart in the landscape. Avoid planting too deep. Soil should be slightly acid and well-drained and amended with organic matter, such as new landscape bed soil. Fertilize at planting with a slow-release fertilizer. Irrigate petunias a couple times weekly to establish them and then once every seven to 10 days when rainfall is lacking.
A new gaura that has performed well as a perennial in LSU AgCenter landscape trials is Sparkle White. This gaura was a 2014 All-America Selections bedding plant winner. Gaura brings airy elegance to the garden with its long, slender stems sporting a large number of dainty white flowers tinged with a pink blush. This beauty is perfect for mass planting in sun-drenched landscape beds, in groupings with other perennials or in larger containers.