Syringa josikaea aka Hungarian Lilac

Hungarian lilac is an easy, low-maintenance shrub once established. It tolerates cold, wind, urban pollution, and poor chalky soils, and is noticeably more resistant to powdery mildew and bacterial blight than common lilac. Choose a sunny spot with well-drained soil and it largely takes care of itself.

Water deeply once a week during the first two growing seasons to establish roots, then only during extended dry spells. Established shrubs are moderately drought tolerant and resent soggy, waterlogged soil more than occasional dryness. Cut back watering from late autumn through early spring while the plant is dormant.

It prefers evenly moist, slightly rich, well-drained loam with a neutral to alkaline (chalky) pH. It tolerates medium and heavy soils but struggles in pure sand and dies in waterlogged ground. A handful of garden lime added to acidic sites helps it thrive.

As a temperate outdoor shrub, Hungarian lilac requires no humidity management and is unaffected by ambient air moisture. However, prolonged high humidity combined with shade and poor airflow can encourage powdery mildew on the leaves. Space plants generously and prune to open the canopy if mildew becomes an issue.

Apply a balanced slow-release fertilizer or well-rotted compost in early spring as growth resumes. A light topdressing of garden lime every few years helps maintain the alkaline pH lilacs prefer. Avoid high-nitrogen feeds, which encourage leafy growth at the expense of flowers.

Hungarian lilac is exceptionally cold-hardy, surviving USDA zones 3–7 and cultivated successfully as far north as arctic Norway and the Faroe Islands. It needs a cold winter dormancy to flower reliably and does not thrive in hot, humid subtropical climates beyond zone 7. Summer heat up to around 30 °C is tolerated if soil moisture is maintained.

It can be grown from stratified seed, softwood cuttings taken in June, semi-ripe cuttings in July or August, simple layering of low branches, or division of suckers in late winter. Softwood cuttings dipped in rooting hormone and kept humid are the most reliable method for home gardeners. Seed-grown plants are variable and slow to flower.

Mature plants typically reach 2–4 m (6.5–13 ft) tall and 2.5–3.5 m (8–12 ft) wide, forming a rounded, vase-shaped, multi-stemmed shrub. Growth rate is moderate, with most plants reaching full size in eight to ten years.

Hungarian lilac produces slender, pyramidal terminal panicles up to 15 cm long of tubular, four-lobed, dark pink to lilac-violet flowers in May and June. Individual florets have a tubular base about 15 mm long with a narrow four-lobed apex 3–4 mm across. It blooms a week or two later than common lilac, extending the lilac season.

Flowers are insect-pollinated, attracting bees, butterflies, and other nectar-seeking pollinators with their strong sweet fragrance. It is not self-pollinating in the sense of requiring a cultivar match, but isolated plants will still set seed thanks to insect visitors. The species hybridizes readily with related lilacs such as Syringa komarowii to produce S. × josiflexa.

Named selections of the true species are few; historical forms recognized in POWO include var. eximia (larger flowers) and var. zabelii, but these are now treated as synonyms. Hungarian lilac is more important as a parent of the Preston hybrid group (Syringa × prestoniae) and of Syringa × josiflexa, crosses with S. komarowii and S. reflexa. These hybrids provide late bloom, cold hardiness, and mildew resistance.

Yes — the flowers carry a strong, sweet, classic lilac fragrance, though many gardeners describe it as slightly softer and less heady than common lilac. The scent is most intense on warm, still mornings and carries several meters on the air. Cut panicles perfume indoor rooms for several days.

Plant in autumn or early spring in full sun, at least 2.5–3 m from other large shrubs, in well-drained neutral to alkaline soil. Water regularly during the first two seasons, mulch lightly (keeping mulch away from the stems), and avoid deep shade. Once established it needs little beyond light annual pruning after flowering.

In early spring, topdress with compost or slow-release fertilizer and check for dead wood. After bloom in June, deadhead spent panicles and do any shaping pruning. In summer, monitor for powdery mildew and lilac borer; in autumn, rake fallen leaves to reduce overwintering disease inoculum; no winter protection is required in its hardiness range.

Prune immediately after flowering, before the plant sets buds for next year. Remove spent flower panicles, cut out dead or crossing branches, and thin about a third of the oldest stems at ground level to rejuvenate the shrub. Avoid heavy late-summer or winter pruning, which removes next season's flower buds and attracts lilac borers to fresh wounds.

Yellowing foliage on Hungarian lilac usually signals waterlogged roots, chlorosis from overly acidic soil, or nutrient deficiency. Check drainage first — the species hates wet feet — then test soil pH and correct toward neutral or alkaline with garden lime if needed. Uniform yellowing in late autumn is normal as the deciduous leaves drop for winter.

Brown patches most often indicate bacterial blight (Pseudomonas syringae), which causes dark, water-soaked spots on leaves and shoots in cool wet springs, or scorch from drought and intense sun on young plants. Prune out affected wood well below the damage, disinfecting tools between cuts, and water at soil level rather than overhead. Hungarian lilac is less susceptible to blight than common lilac but not immune.

Sudden wilting of individual branches usually points to lilac borer tunneling inside the stems — look for small exit holes with frass near the base. Whole-plant wilting in hot weather indicates under-watering or root rot in poorly drained soil. Remove and destroy infested stems and improve drainage or irrigation as appropriate.

Autumn leaf drop is normal — Hungarian lilac is deciduous and sheds its foliage each winter. Premature summer drop usually indicates severe powdery mildew, drought stress, or root damage from waterlogging. Water deeply during dry spells, improve airflow around the shrub, and rake and dispose of fallen leaves to reduce disease carryover.

The most common causes are too much shade, acidic soil, excess nitrogen, or pruning at the wrong time of year. Lilacs flower on shoots produced the previous summer, so any pruning after July removes next year's blooms. Move the plant into full sun if possible, add lime to raise pH, switch to a balanced or low-nitrogen feed, and prune only immediately after flowering.

Hungarian lilac is notably resistant to powdery mildew and bacterial blight compared with common lilac, but can still be affected by lilac borer (Podosesia syringae), scale, aphids, lilac leaf-miner, and lilac witches' broom. Powdery mildew may appear in late summer, especially in shaded or crowded sites. Good airflow, full sun, and removing dead wood go a long way toward prevention; there is no effective chemical cure for borer larvae once inside the stems.

No part of Hungarian lilac is considered edible and it has no documented food use. Plants For A Future rates its edibility 0 out of 5 with no edible parts known. While flowers of some Syringa species are used ornamentally in baking, there is no tradition of culinary use for this species specifically.

Hungarian lilac has no documented medicinal applications. Plants For A Future rates its medicinal value 0 out of 5 and lists no traditional or modern remedies using the species. It should not be used for self-treatment.

It is widely planted as an ornamental — as a specimen, in shrub borders, and as an informal hedge that tolerates trimming well. It provides fragrant cut flowers in early summer and serves as a rootstock for grafting other, less vigorous lilacs. Its late bloom and cold hardiness also make it a valued parent in breeding programs, contributing to the Preston (S. × prestoniae) and josiflexa (S. × josiflexa) hybrid groups.

Hungarian Lilac’s native range is Europe - Hungary.

Hungarian Lilac requires abundant, bright, and direct light to thrive. The best placement for this plant is within one foot of a window to ensure it receives enough light. If you live in an area with more extreme weather, such as hot summers or cold winters, you may need to adjust the placement of the plant accordingly. During hot summer months, it is important to place the plant away from full sun, as this can cause the leaves to yellow or burn. During cold winter months, it is best to move the plant closer to the window to take advantage of the extra light that can help it survive. By keeping an eye on the current weather in your area, you can make sure your Lilac is always in the right place to thrive.

There is no verified data on the toxicity of this plant in the records of Ploi. If any person, including yourself, a family member, or a pet, consume plant material with an uncertain toxicity level, it is advisable to seek the advice of a healthcare expert.