Syringa oblata is a deciduous shrub renowned for its early-blooming lilac flowers, which emit a sweet fragrance. Broad heart-shaped leaves and a rounded growth habit characterize this plant, typically thriving in temperate climates. Its flowers, ranging from pale purple to lilac-pink, form dense clusters that attract pollinators and are a harbinger of spring.
I. Appearance and Characteristics
Syringa oblata is a species in the genus Syringa, in the family Oleaceae. It is also known as early blooming lilac or broadleaf lilac.
Oblata from the modern Latin oblatus, meaning ‘somewhat flattened at the ends, oval, oblate’. Syringa is derived from the Greek word syrinx, meaning ‘pipe’ or ‘tube’. Named for the use of its hollow stems to make flutes. In Greek mythology, the nymph Syringa was changed into a reed.
Similar to Syringa vulgaris, but flowers earlier and has very different leaves. Most commonly seen lilac species in China.
- Height: Shrub or small tree to 3.5m or 5m.
- Stems: May be glabrous, pubescent, or puberulent (with fine, minute hairs). Shoots are glabrous.
- Leaves: Ovate-orbicular to reniform, often slightly wider than long, measuring 2.5-10 (occasionally up to 14) cm x 2.5-8 (occasionally 15) cm. Leaves range from glabrous to pubescent, villous, or glabrescent (losing hairs with age). Base is truncate to subcordate or broadly cuneate, with an abruptly acute to long acuminate apex. Leaves colour well in fall, often turning to shades of red in autumn.
- Flowers: Panicles are lateral, congested, lax, or erect, and measure 4 – 16 (occasionally as much as 20) cm x 3 – 8 (occasionally 10) cm. Pedicel to 3 mm in length, and may be either pubescent or glabrous. Corolla is about 1.3 cm long and 1.7 cm across, and ranges from purple to lilac, and occasionally white; tube is subcylindric, and measures 0.6 – 1.7 (occasionally up to 2.2) cm in length. Calyx is slightly glandular. Lobes are oblong to obovate-orbicular or ovate-orbicular and measure 4 – 8 (occasionally 10) mm, spreading. Anthers are yellow, inserted in corolla tube to 4 mm from the mouth. Flowers are fragrant and appear earlier than any other species of Syringa, from April to May and June.
- Fruit: Smooth obovate-elliptic to ovate or oblong-lanceolate capsule measures 0.7 – 1.5 (rarely 2) cm.
II. How to Grow and Care
Syringa oblata thrives in temperate climates and requires well-drained soil with moderate moisture. Special care includes ensuring it receives full sun to partial shade for optimal flowering. Pruning is essential right after blooming to maintain shape and encourage future blooms. Overall, syringa oblata is easy to care for, making it suitable for gardeners of all levels.
Sunlight
Syringa oblata likes sufficient sunlight, and 6-8 hours of direct sunlight per day will ensure vigorous growth and blooms. Without sufficient sunlight, the growth is slow and barely blooms, or not at all.
Temperature
Plants of genus Syringa are mainly distributed in the subtropical and temperate zone, where the environment is warmer, and also grows at high elevation. Some varieties can tolerate high temperatures, but the ornamental effect is decreased. Different species and varieties have different bloom times, extending from mid-spring to early summer. It does not have strict water requirements and is resistant to drought.
Watering
Originating from the woodlands, syringa oblata thrives in moderately moist soil conditions, mirroring its native environment’s balanced humidity. It exhibits a preference for consistent moisture without being waterlogged, showing moderate drought tolerance once established. Watering should be done once every 1-2 weeks to maintain optimal hydration. Indoors, syringa oblata benefits from higher humidity levels to emulate its natural habitat, making it important to consider room humidifiers or pebble trays to increase ambient moisture. During the growing season, ensuring adequate water is crucial for syringa oblata’s health and vitality.
Soil
Syringa oblata can endure poor soil and adapts to various soil types, but it is sensitive to acidic soil. It prefers well-drained, loose, fertile soil which is neutral to alkaline (pH close to or higher than 7). It should not be planted in low-lying areas, because long-term accumulated water can cause poor growth and even death. If the soil in the garden is not fertile enough, add compost, bone fertilizer or other fertilizers.
Fertilizing
For syringa oblata, apply balanced nutrition fertilizers in spring for vigorous growth, switching to high-nitrogen variants to promote lush foliage. Biannually, before new growth and mid-summer, is optimal, with quantities per label instructions. Benefits include enhanced flowering and overall health. Avoid over-fertilization to prevent root damage. Seasonal adjustments ensure tailored nutrient provision, with a lighter hand during dormant periods. Practical tip: water syringa oblata post-fertilization to help nutrient absorption and prevent root burn.
Planting Instructions
Select varieties with bloom time, color, and height you prefer. Syringa oblata can be transplanted after leaves fall off in the fall or after the soil is defrosted in spring. If transplanted in the fall, plants can form a root system before the next bloom season and perform well. Transplanting in spring can prevent the seedlings from freezing in the harsh winter and increase the survival rate. If transplanted in summer, leaf buds and flower buds grow quickly. However, excessive evaporation of the aboveground part may negatively affect its growth and blooms for the following year.
If you can buy two-year-old or older saplings from the nursery, they will blossom the same year or the following year. Ramets can be dug from mature syringa oblata for transplanting. Care should be taken to ensure that the seedlings are at least 30 cm tall. It may take 3-4 years for these smaller seedlings to blossom.
When transplanting a seedling, dig a pit 5 to 8 cm larger than the earth ball and twice its diameter. Stretch the roots of the seedling out and put them into the pit. Cover the pit with soil mixed with compost. Water the pit when half the soil is filled in, then continue to fill in soil. The filled soil should be kept level with the ground. Also make sure that the top layer of the root system is several inches under the soil surface, so the root system is completely buried. Water thoroughly after planting, and then once every 10 days, 3-5 times in succession, for strong root establishment. Depending on the variety, space the plants 1.5 to 4.5 m apart.
Pruning
Pruning is essential for syringa oblata, because it promotes blooming, ensures air circulation, and prevents problems such as powdery mildew. Prune the plant every year to keep it in its shrub form. If it is not pruned, it will grow to 4.5 to 6 m, and the blooms will gather at the plant top. Because very young and old branches do not bloom well, regular pruning is required to keep it blooming beautifully every year.
Generally, branches with a diameter of 5 cm or more should be pruned off. Prune less than 1/3 of all branches and keep 8-12 branches of different ages with a diameter of 2.5 to 5 cm. Finally, maintain the plant at 2.5 m tall or less.
Old, dead, and diseased branches, and most seedlings growing from the roots, can be cut from the base after blooming at the end of winter or late spring. The old branches are usually coarse, with weak blooming ability. Dead and diseased branches will not grow new buds or flowers in spring. Keep 2-3 strong seedlings as new branches. Any branches that disturb the tree shape or are twisted can be pruned at the same time.
If you do not need to harvest the seeds of the syringa oblata, cut blooms off when they begin to fade and droop. This prevents nutrient use for fruit development, and next year’s flower buds will be stronger. When the center of the tree is overcrowded, choose the thickest stem and cut it off at the base to improve sunlight and ventilation inside the shrub.
If your syringa oblata is old, overgrown, or blooming poorly, the whole plant can be pruned to 15 to 20 cm tall. It will not bloom for three years, but the number of flowers will increase significantly.
Propagation
Syringa oblata, a member of the Oleaceae family, can be successfully propagated using cuttings. For optimal results, select healthy, semi-hardwood stem segments. These should be taken with care to include at least one set of leaves for photosynthesis and a node, which is critical for root development. Apply rooting hormone to the cut end to encourage growth and plant in a well-draining soil mix. Keep the soil moist and provide indirect light until roots establish.
Transplanting
For a thriving syringa oblata, transplanting from the thaw of winter to the full swing of spring, when active growth begins, is ideal. Choose a sun-kissed spot with well-draining soil, ensuring minimal root disturbance for best establishment.
III. Harvesting and Storage
Blooms can be used as excellent fragrant cut flowers with a vase life of 3-5 days. Cut off the stalks and insert them into the vase when about 1/3-1/2 of the flower buds bloom. Cut at the bases of the branches with sharp scissors, not broken by hand. Syringa oblata can produce many flowers each spring. However, don’t cut too many stalks from a sapling blooming for the first time; otherwise, it will impact the growth of the sapling.
You can also dry syringa oblata flowers. Tie the fresh stalks into a bunch with a rope, and hang them upside down in a dry, airy place for 1-3 weeks. After the flowers are completely dry, take them off gently and appreciate them as dried flowers.
