Perennial Solutions: Azalea ‘Encore Autumn Fire’
Azaleas are great shrubs for bringing lots of color into spring landscapes. Over the years, the breeding efforts of renowned breeder Buddy Lee has led to the introduction of the Encore series, which provides multiple seasons of beautiful blooms. ‘Encore Autumn Fire’ (rhododendron ‘Roblez’) is one of the most recent introductions to this remarkable series of reblooming azaleas.
‘Encore Autumn Fire’ is a dwarf azalea growing 2½ feet tall by 3 feet across which boasts a tremendous display of lush, large 2½-inch true red semi-double blooms in the spring. Additional flushes of blooms develop in the summer and again in the fall. The attractive evergreen foliage also provides year round seasonal interest with its glossy, dark green coloration during the growing season that darkens to a saturated purple bronze during the winter months.
Azaleas are members of the Ericaceae family, which includes other well known ornamentals including rhododendrons, heaths and heathers as well as popular fruit crops like cranberries and blueberries. ‘Encore Autumn Fire’ performs best in locations with light, filtered afternoon shade and moist, but not wet, soils throughout USDA Hardiness Zones 6 to 9. In the deep South or in the hotter regions of the country, azaleas prefer locations with morning sun with afternoon shade.
Azalea ‘Encore Autumn Fire’ is a great ornamental plant that livens up the landscape with bright colors throughout multiple seasons. Although not a traditional perennial, this reliable shrub provides ornamental value in the landscape for numerous years. With its multi-seasonal landscape appeal, reliable performance and ease of production, ‘Encore Autumn Fire’ is a great choice for borders, mass plantings or in attractive patio containers. This great plant can help growers extend their retail sales into the summer and fall months of the year.
PROPAGATION
Azalea ‘Encore Autumn Fire’ is propagated vegetatively from softwood cuttings. They are patented; therefore, propagation without a license is strictly prohibited.
PRODUCTION
Azalea perform best when they are grown in a moist, welldrained growing mix. Many commercially available peat- or barkbased growing mixes work well provided there is good water holding ability and adequate drainage. Avoid mixes that hold on to too much water or ones that dry out quickly.
‘Encore Autumn Fire’ is typically produced in 1- to 3-gallon containers. Plant a single large liner (3-inch) into 1-gallon containers. With larger containers, it is best to plant two or three liners into each pot to provide more fullness and to decrease the production time. The liners should be planted so the original soil line of the plug is even with the surface of the growing medium of the new container. ‘Encore Autumn Fire’ can be planted at various times of the year depending on the container size and desired market date (scheduling is discussed below).
They have an average water requirement prior to becoming established but will require more frequent irrigations as the plants mature. Avoid letting them reach a hard wilting point or foliage burn may occur. When irrigation is needed, water them thoroughly, ensuring the entire root zone is wet or nearly saturated and then allow the growing mix to dry slightly before the next irrigation is applied.
Azalea require average amounts of nutrients, requiring slightly fewer nutrients than many other shrub varieties. Like with most shrubs, controlledrelease fertilizers (CRFs) are the most common method of delivering nutrients. CRFs can be incorporated or topdressed using a rate which falls between the specific products low and medium rate recommendations. Apply 200 ppm of nitrogen with each irrigation or 400 ppm as needed when using water-soluble fertilizers. They prefer slightly acidic conditions; the pH should be maintained between 5.5 and 6.0.
With its free branching habit, it is not usually necessary to prune or trim ‘Encore Autumn Fire’. Light pruning to established plants will stimulate additional growth and flowering. Tall shoots can be trimmed back inside the body of the plant. Since they set flower buds on new growth, if trimming is necessary, it is best to trim them immediately after the spring flush of flowers. Pruning later in the growing season will likely remove some of the flower buds developing for the summer or fall blooming periods. Also avoid trimming them too late in the growing season; pruning in the fall can reduce the number of flowers which develop for the spring blooming cycle.
‘Encore Autumn Fire’ has a compact growing habit and usually will not require any height management strategies. Providing adequate spacing between the plants will reduce plant stretch caused by competition. If toning is required, spray applications of 500 to 2000 ppm daminozide (B-Nine or Dazide) can be applied as needed.
INSECTS AND DISEASES
Azaleas can be produced with relatively few problems from insect feeding or plant pathogens. Lace bugs (Stephanitis pyrioides) and spider mites are the most common insects observed feeding on them. Although azalea can be generally grown without the incidence of plant pathogens, several pathogens may be observed during production.
The most common plant diseases are Botrytis petal blight (gray mold on the flower petals), Ovulinia petal blight (irregular shaped white spots on the flower petals, become wet looking and slimy), Phytophthora root rot (typically occurs when the plants are kept too wet) and Rhizoctonia (aerial blight). Routine scouting will allow for early detection of these problems and can be useful to determine if control strategies are necessary.
TEMPERATURE AND SCHEDULING
The most prolific flowering occurs in the spring. Plants for this sales window should be planted during the late spring or early summer the year before they are to be sold. After the dormant period, they can be forced into flower in four to five weeks with temperatures between 59° F and 68° F.
Any plants not sold can be flushed into bloom for summer or fall sales. The flower buds for summer flowering develops on new growth after the initial flush of flowering occurs in the spring. If flowering is desired, avoid trimming the plants or only trim to shape them after the spring flowering. Otherwise, new plantings of ‘Encore Autumn Fire’ can be planted in the spring for these late season sales.
AVAILABILITY
The Encore series of azalea are only propagated by licensed propagators. The list of licensed growers is too long to provide here; however, it can be obtained at the following website: www.encoreazalea.com/marketingresources/ growers.
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