The ironwood tree’s fiery show
The Persian ironwood is a flame-leaved beauty that provides a dazzling finale to the autumn season
d own at the end of a garden, the air sits heavy with the scent of woodsmoke as a small bonfire burns. There is a snap and a pop as the flames devour the pile of non-compostable woody stems and pernicious weeds collected during an afternoon tidy-up. The rapidly changing hues of red, orange and yellow in the flickering flames are echoed elsewhere in the autumn garden where, along the treeline, the leaves are saving the strongest colours for their swansong. One of the most spectacular of all trees in autumn is the Persian ironwood, Parrotia persica. Its ageing foliage brings a wonderful richness to the autumn garden, like a fire being prodded, sending up glowing shades of gold and burnt orange, before darkening to red and then purple. Once the leaves have dropped, the bark of this tree also peels to reveal its own colourful show. Parrotia persica needs no other partner to enhance its aesthetic appeal. However, it lifts the muted tones of ornamental grasses and perennial seedheads late in the season if planted behind them at the back of a border. When lower branches are pruned, it can make for the most elegant of avenue trees. Left to spread, it becomes a majestic autumn symbol, a mature tree capable of growing 26ft (8m) tall
in the UK. Despite its potential size, it is slow-growing and will take at least 20 years to reach this height. The leaves of P. persica are similar in shape to those of its close relative, the highly fragrant, winter flowering witch hazel. They have prominent herringbone veining running down the outer surface.
Tough species
As the common name, Persian ironwood, and species name, persica suggests, this tree originates from mountainous regions in what was Persia, now northern Iran, and also Azerbaijan. It is thought to have been grown in the UK for the first time in 1846 at the Royal Botanic Gardens, Kew, after two small pot plants were sent there from St Petersburg, Russia. The tree was given the name parrotia not because of the magnificent autumn leaf colour resembling a parrot’s plumage, but in honour of German naturalist and mountaineer Dr Friedrich Wilhelm Parrot, 1792-1841. Parrot led the first recorded expedition to the summit of Mount Ararat, on the border of Turkey and Iran, in September 1829. The tree was named after him by French botanist Carl Anton Meyer, who discovered that it could not be a witch hazel as had been previously thought because its flowers did not have petals. Originally given the Latin name Hamamelis persica, the plant was reclassified. The bark is another attractive feature of this tree and takes centre
stage once all the leaves have fallen at the end of autumn. Like the leaves, the bark displays a mix of colours. As the tree ages, the silvery bark starts to flake. Underneath, it reveals a mix of cream, green, grey, pink and yellow juvenile hues that can be just as appealing to the eye as the autumn foliage. When the bark flakes, it produces an intricate curvaceous, mottled patchwork, not dissimilar to that of that classic street tree, the London plane, Platanus x hispanica.
Plant care
Forming such a naturally beautiful, oval-shaped tree, before gently spreading wider as it ages, Parrotia persica does not need a lot of pruning or training. However, any branches that are crossing into others are best removed completely at an early age. This improves airflow around the branches and prevents the tree from becoming congested with thick branches, which can be difficult and expensive to rectify in a mature tree. The tree should also be inspected at the end of autumn to spot any branches that have been broken by gales. These should be removed by making a clean cut back to a side shoot or removed completely. If growing a young specimen as a lollipop-shaped standard tree, low branches are pruned out flush with the trunk, to maintain the shape. All pruning should be carried out in winter before the sap starts to flow. This
reduces the risk of pruning cuts becoming infected. Sharp tools should always be used when pruning, to leave clean cuts, which will reduce the risk of disease later on. The only other maintenance needed for this tree is regular watering in dry spells during the first two years after planting. The soil should be thoroughly soaked around the base of the plant if no rain falls for a spell of two weeks in spring and summer. Although the tree can tolerate drought once established, it will not be able to in the first two years. It will never truly thrive in drought and may shed leaves early during the growing season in very dry spells. Thorough watering in summer drought conditions will help even established plants. The best soil for Persian ironwood is moist and fertile, and drains well. If water stands on the surface during winter, then the soil is not free-draining enough. Thin, chalky soils, which dry out quickly in summer, are also best avoided because leaves are likely to drop prematurely, and there may be no autumn show at all. P. persica is likely to produce the best display of autumn leaf colour when grown in acid soil in a site that receives sun for most of the day. If rhododendrons, skimmias or camellias are growing healthily close by, with glossy green foliage, this indicates acid soil. Failing this, a soil-testing kit, available from a garden centre, will ascertain whether or not the soil is acidic.
Slow growth
Parrotia persica can be propagated by taking cuttings of new growth at the end of summer, when the base of the stems are woody but the stem tips are still soft. As it is very slow-growing and it will be many years before a cutting makes even a small garden plant, it is best to purchase a tree from a specialist nursery to increase any stock. The sight of a mature Parrotia persica in its full autumn glory is too magnificent a moment to wait for any longer than necessary. An autumn without one is an opportunity missed.