Oak Trees

Twenty six oak listings, four of them Quercus palustris. Pin oak comes as the straight species plus three selections that fix or dodge its faults, and behind it a tail of rarely grown species. Every line is full sun and slow to moderate growth.

The pin oak fork

A standard pin oak holds dead brown leaves most of winter, dropping them only when spring growth pushes. Over a lawn nobody minds. Over a car park, a pool or a swept street it generates complaints. Two listings answer that. Freefall is grafted, so form stays even down a row, and it colours then drops cleanly. Early Drop Form does the same job from a different farm on a different size run, bare root included. Open both and compare grades. Green Pillar is the narrow one, near columnar without pruning, for a nature strip or a boundary a few metres wide, though it still hangs on to leaves into early winter. Only Pin Oak - Quercus palustris runs the whole ladder, from a 200mm pot of about four and a half litres to 1000L and bare root.

All four hate lime. On alkaline ground the leaves yellow between green veins and stay that way. Test your pH first. On calcareous sand behind the Perth coast, or over Adelaide limestone, plant Bur Oak, Turkey Oak, Holly Oak or Texas Red Oak instead.

Soil picks your oak

Bur Oak takes alkaline soil, heavy clay, wind and cold better than a pin oak does. Its acorns are fat, shaggy cupped, and drop over weeks, so keep it off paving. Turkey Oak and Texas Red Oak both handle dry, exposed, alkaline country. For the opposite problem, Swamp White Oak copes with compacted ground that floods after rain, and Willow Oak tolerates heavy clay and periodic wet better than most of the genus. Water Oak forgives wet feet too, though its timber is soft for an oak and old trees shed limbs in storms. All three want acid to neutral soil, and lime yellows them too.

Autumn colour is a district question

Scarlet Oak gives a genuine red in cool districts, the Southern Highlands, the Adelaide Hills, central Victoria, and runs to bronze in warm coastal gardens. Shumard Oak colours reliably in warm districts where a pin oak just browns off.

The five evergreens

Cork Oak, Holly Oak - Quercus ilex, Portuguese Oak, Algerian Oak and Engelmann Oak keep their leaves. Cork Oak is the dry summer specialist, at home around Adelaide, inland Victoria and the western slopes. It will not tolerate waterlogging. Holly Oak clips, and pleaches into a raised hedge on clean stems. That shade is dense and permanent, so an evergreen oak north of the house blocks winter sun too.

Which grade to buy

Growth is unhurried, so the grade you buy is most of the wait, with one exception. Oaks send a taproot down early, and a tree held too long in a large pot arrives with that root kinked or cut and never anchors. For Valley Oak especially, buy small or bare root. Ten of the twenty six start at a 200mm pot. Twenty one offer a 400mm pot, roughly 35 litres, a sensible floor otherwise. Five carry bare root grades through winter, the practical way to plant an avenue. Three come in one grade only: Shumard Oak at 200L, Texas Red Oak at 50L, Pyrenean Oak at 20L.

Oaks sulk in shallow or compacted ground, so break up any hardpan and dig wide rather than deep. Acorns are high in tannins and can poison horses and cattle, so fence stock out of the drip line on a paddock or rural entry.

If your block is suburban, this is the wrong page. English Oak finishes as wide as it stands tall, and Valley Oak will outgrow the block and then the neighbours. Read Trees for small backyards first.