Evergreen azalea (Rhododendron 'Treasure')
Rhododendron 'Treasure' is a showy Evergreen azalea, ideal for zones 6-8, featuring white blooms and medium maintenance needs.
Scroll down to discover growing tips, care requirements, companion plants, and more
Complete Plant Information
Overview
Rhododendron ‘Treasure’ is a highly valued Evergreen azalea, celebrated for its robust structure and attractive springtime display. This broadleaf evergreen holds onto its foliage throughout the year, providing essential textural contrast in mixed plantings, especially during winter months. Gardeners prize this cultivar for its manageable size, typically reaching 4 to 6 feet tall and wide.
As a hybrid of R. ‘Fielder’s White’ and R. Kaempferi, Rhododendron ‘Treasure’ offers reliable performance in USDA Zones 6 through 8. Its primary aesthetic draw is the beautiful spring bloom of white flowers subtly edged with very light pink spots on the lobes. Successful cultivation of Rhododendron ‘Treasure’ hinges on replicating its preferred woodland environment.
This plant excels when placed in locations receiving dappled sunlight or high open shade, offering functional beauty as a specimen, in mass plantings, or as a formal hedge. Its medium water and maintenance requirements make Rhododendron ‘Treasure’ a rewarding choice for gardeners committed to providing the proper acidic soil conditions.
Fast Facts
- Plant Family: Ericaceae
- Plant Type: Broadleaf evergreen
- Hardiness Zones: USDA Zones 6-8
- Size at Maturity:
- Height: 4-6 ft
- Spread: 4-6 ft
- Bloom Time: April to May
- Bloom Description: White
- Sun Exposure: Part shade
- Water Needs: Medium
- Maintenance Level: Medium
How to Grow
Planting Rhododendron ‘Treasure’ correctly sets the foundation for long-term health. Aim to plant in spring or early fall when temperatures are moderate. The most critical requirement is the soil: it must be acidic, organically rich, humusy, and consistently moist but extremely well-drained. Avoid locations where water pools, as this quickly leads to root rot, a significant issue for evergreen azaleas. If you have heavy clay, consider planting in raised beds to ensure adequate drainage.
Watering should be consistent, falling into the ‘Medium’ category; roots must never be allowed to dry out, even briefly. Apply a thick layer of organic mulch, such as wood chips or pine needles, around the shallow root system to stabilize temperatures and retain moisture. Fertilize only if necessary to maintain the preferred soil pH of 5.0 to 5.5, using iron sulfate or sulfur to acidify as needed.
Maintenance for Rhododendron ‘Treasure’ includes regular deadheading—clipping off spent flower clusters shortly after blooming concludes—to encourage energy conservation for next year’s display. Protect plants from strong winds. Crucially, never cultivate or till near the base of the plant, as its fibrous roots are shallow and easily damaged. Also, avoid planting near walnut trees due to allelopathic compounds (juglones).
Landscape Uses
Rhododendron ‘Treasure’ offers exceptional versatility in landscape design, serving effectively in various capacities. Its formality makes it an excellent choice for structuring shrub borders or defining edges. When planted closely, these Evergreen azaleas function beautifully as medium-height evergreen hedges where year-round structure is desired.
Beyond formal uses, Rhododendron ‘Treasure’ integrates seamlessly into woodland gardens and shade gardens, providing excellent understory interest beneath taller, dappled-shade trees. They are also effective as component plants in mixed borders or for softening the foundation plantings around structures. Their bloom time in mid-spring offers a crucial burst of white color early in the season.
Companion planting should focus on species that share the acidic soil and part-shade requirements. Consider pairing with acid-loving ferns, hostas, or smaller deciduous rhododendrons that complement the evergreen texture of Rhododendron ‘Treasure’.
Standout Features
Flower Qualities
- Showy
Noteworthy Characteristics
Rhododendron is a genus of 500 to 900 species and includes both of what we commonly call rhododendrons and azaleas. Evergreen azaleas develop as multi-stemmed plants from the ground and usually grow 3-5 feet tall, retaining their leaves throughout the year. The cultivar ‘Treasure’ is a Morrison hybrid that features striking white flowers punctuated by very light pink spots and edging along the lobes.
Tolerances
- Rabbit
Potential Problems
Rhododendrons and azaleas, including Evergreen azalea ‘Treasure’, are targets for various insect and disease issues if environmental conditions are stressed. Common insect pests include aphids, lacebugs, and scale, while diseases might manifest as root rot or leaf spot if drainage is poor. Chlorosis, which causes yellowing leaves, frequently points to an iron deficiency resulting from improperly high soil pH. Maintaining the correct acidic soil range (5.0 to 5.5) is the primary preventative measure against many cultural problems. Ensure excellent air circulation and avoid overhead watering late in the day to minimize fungal risks.
Frequently Asked Questions
What hardiness zones is Evergreen azalea (Rhododendron ‘Treasure’) suitable for?
Rhododendron ‘Treasure’ thrives in USDA Hardiness Zones 6 through 8.
How large does Rhododendron ‘Treasure’ grow?
This cultivar typically matures to a height and spread between 4 and 6 feet.
What sun exposure does Evergreen azalea need?
This Evergreen azalea performs best in part shade, preferring sun-dappled conditions or high open shade.
When does Rhododendron ‘Treasure’ bloom?
Rhododendron ‘Treasure’ is noted for its bloom time from April to May, producing white flowers.
Conclusion
The Rhododendron ‘Treasure’ Evergreen azalea provides reliable, year-round structure coupled with a delicate white springtime floral show, making it indispensable for acidic woodland-style gardens. By carefully managing soil acidity and ensuring flawless drainage, gardeners can ensure robust health for their Rhododendron ‘Treasure’ specimens. Always check your local climate suitability before planting this beautiful cultivar.
Companion Planting
Selecting neighbors that appreciate similar conditions helps maximize the garden ecosystem around your Rhododendron ‘Treasure’. Plants that thrive in acidic, humus-rich, part-shaded environments are ideal partners. Consider delicate woodland ferns, which offer textural contrast without competing aggressively for shallow nutrients.
Hosta varieties with blue or dark green foliage look stunning beneath the bright white flowers of the Evergreen azalea in the late spring. For year-round evergreen structure, low-growing dwarf conifers adapted to partial shade make excellent groundcovers or border accents near the base of the azalea.
Seasonal Care Calendar
Spring preparation for Rhododendron ‘Treasure’ is crucial; once blooming concludes in May, gently deadhead the faded flowers to direct energy toward root and foliage growth, not seed production. Apply a fresh layer of acidifying mulch, like pine straw, immediately afterward.
During the heat of summer, monitor moisture levels vigilantly, especially in Zones 7 and 8, as the shallow roots dry out quickly. Avoid high temperatures in the afternoon sun, which can scorch the foliage. In autumn, ensure the plant is adequately hydrated entering dormancy; do not apply fertilizers low in nitrogen or those containing lime.
In winter, protect the evergreen foliage from excessive winter burn, particularly when exposed to drying winds in Zone 6. Adding a temporary burlap screen on the side facing prevailing winter winds can significantly reduce foliage desiccation for your Rhododendron ‘Treasure’. If chlorosis appears, apply chelated iron or elemental sulfur to correct soil chemistry before the next growing season.
