Pelargonium quercifolium aka Oakleaf Geranium

Pelargonium quercifolium is a relatively fast-growing evergreen shrub that typically reaches 1 to 1.75 meters (3-6 feet) in height with a spread of 0.75 to 1 meter (2.5-3 feet). Young stems are soft and covered with fine glandular hairs, becoming woody and brown as the plant matures. The much-branched growth habit creates a bushy, dense form that takes 2-5 years to reach full maturity.

Pelargonium quercifolium is frost-tender and can tolerate minimum temperatures of around -3°C (27°F) for brief periods. It thrives in USDA zones 8-11. In cooler climates, it must be overwintered indoors or in a frost-free greenhouse. The plant is remarkably resilient and can be overwintered at cool temperatures as low as 5-6°C (41-43°F), though with higher temperatures and ample light it will continue growing and blooming throughout winter.

Pelargonium quercifolium has strongly aromatic foliage with a distinctive balsam or resinous scent, sometimes described as almond-like or reminiscent of incense. When the sticky, deeply-lobed leaves are bruised or crushed, they release a warm, pungent aroma. The essential oil has a laudanum fragrance. Despite sometimes being sold as a 'scented geranium', its fragrance is more resinous than sweet.

Pelargonium quercifolium produces clusters of 2-6 relatively large flowers in umbel-like inflorescences. The blooms are lilac-pink to pinkish-purple with distinctive reddish-purple or dark markings. In its native South African habitat, it flowers from August to January with sporadic blooming throughout the year. In Northern Hemisphere gardens, expect flowers from late spring through summer (May to July). With adequate light and warmth, indoor plants may continue blooming through winter.

Several notable cultivars of Pelargonium quercifolium are available. 'Fair Ellen' features almond-scented leaves with dark central blotches and deep mauve flowers with dark markings. 'Royal Oak' has similar characteristics with prominent dark leaf veins and a resinous, almond-balsam scent. 'Giant Oak' is prized for its particularly large, heavily-scented leaves. All cultivars share the characteristic oak-shaped foliage and aromatic properties of the species.

Pelargonium quercifolium can grow outdoors year-round in USDA zones 9-11 where frost is rare. In zone 8, it may survive with winter protection. In cooler climates, grow it outdoors from late spring after all frost risk has passed, then bring indoors before the first autumn frost. The plant thrives in south or west-facing positions with full sun and well-drained soil. It tolerates exposed conditions once established.

Pelargonium quercifolium is very tolerant of pruning and should be pruned frequently after flowering to maintain a compact, bushy shape. Deadhead spent blooms regularly to encourage continued flowering. Hard pruning can be done after the main flowering period to rejuvenate leggy plants. The plant responds well to shaping and will produce new growth readily from woody stems.

Repot Pelargonium quercifolium in spring before the main growing season begins, typically every 1-2 years or when roots become crowded. Use a well-draining potting mix with added sand or perlite for drainage. Choose a pot only slightly larger than the previous one, as pelargoniums bloom better when slightly pot-bound. Ensure the container has adequate drainage holes to prevent waterlogging.

Pelargonium quercifolium propagates easily from cuttings or seeds. For cuttings, take 15cm (6 inch) semi-mature stem cuttings preferably after flowering, apply rooting hormone, and root in coarse river sand. Cuttings typically root within four weeks. For seeds, sow at 2-3mm depth in light, well-drained potting soil at minimum 13°C (55°F). Germination usually occurs within 2-4 weeks. Cuttings can be taken almost any time but early summer gives best results for establishment before winter.

While SANBI notes no documented pest or disease issues in its native habitat, cultivated plants may be susceptible to common pelargonium problems. Watch for vine weevil, mealybugs, aphids, whitefly, thrips, and caterpillars. Fungal issues include grey mould (Botrytis), blackleg, and pelargonium rust. Viral diseases can also occur. Good air circulation, avoiding overwatering, and removing affected plant material help prevent most problems.

Pelargonium quercifolium has no known edible uses and is rated 0 out of 5 for edibility. While the leaves are highly aromatic and used in potpourri and essential oils, they should not be consumed. The plant contains essential oils (linalool and geraniol) that can cause gastrointestinal upset if ingested. This species is grown for its ornamental and aromatic qualities rather than culinary purposes.

Pelargonium quercifolium has a moderate medicinal rating (2/5) with traditional uses in South African folk medicine. All parts of the plant are astringent, and it is described as an aromatic, stimulant herb. Fresh infusions have been used internally for treating rheumatism, hypertension, and heart disease. The plant can be harvested fresh year-round for medicinal preparations. As with all herbal remedies, consult a healthcare professional before use.

Beyond ornamental gardening, Pelargonium quercifolium has several practical uses rating 3 out of 5. The aromatic leaves are excellent in potpourri and insect-repellent sachets. Essential oils with a distinctive laudanum fragrance can be extracted from the plant. The bruised leaves release a warm, incense-like aroma. Additionally, the plant functions as a dynamic accumulator and attracts butterflies to the garden.