It is the start of the traditional tree-planting season and a good time to plant trees that make huge size. Of the limited list of trees capable of making great size in this country, only a couple are natives. Oak, ash and black poplar are the only species that make really big trees and even then there is some doubt as to whether the black poplar can be considered native.

Oak can grow to a big tree because it is very long-lived. If it is left to grow large, it can eventually produce a huge broad trunk and the side branches will themselves root into the ground and become trunk-sized. Ash mostly is seen as a medium-size tree but on fertile ground it can grow to over 25m, a big tree by any standards, but often drops branches when it gets really big. The black poplar can make a very big tree on occasion reaching to 30m and more with a big round trunk and heavy branches.

Although there are not many large native tree species, there are several more that are native to Europe and these generally do very well here and can make large size. Beech is an obvious example, so commonly grown that it is often taken as native. It grows well in fertile soil making large size to over 30m exceptionally. Sweet chestnut, or Spanish chestnut, is used to warmer climate than here but can make a very large tree in rich soil. It is a long-lived tree and very old, gnarled specimens with a massive, but usually short, trunk are sometimes seen, especially on old estates.

The silver fir is native to Europe, a massive conifer commonly seen towering above other trees in old estates, often with a tufted branch sticking out at the top, as much as 10m clear of all its surrounding trees. This was the tallest conifer until the North American conifers arrived in the middle of the nineteenth century. Common lime is native to Europe and makes a big tree with a mass of suckers at ground level or higher up where the main branches arise. This can look a bit messy but the lime is a superb large tree capable of over 30m.

Cedar is native to north Africa or Lebanon, likes warm conditions and does best in warmer parts on well-drained but fertile, deep soil. It makes a very big trunk with a broad flattened top when mature. The California redwoods are the world’s tallest and biggest trees and the two sequoia species grow well here. There are plenty of examples of trees well over 30m tall. The biggest problem for this tree when planted individually is lightning strike which can smash the tip and cause distorted growth.

Sitka spruce is native to Alaska and thrives in the cool damp climate here. It is generally not seen as a really big tree, but it can make a huge tree to over 40m with a massive trunk and also although wind-resistant, it grows best in a valley setting.

Douglas fir is another North American giant, and does best in relatively warm locations in well-drained fertile soil, a clean stem to 20m and more, and another 15-20m above. The western red cedar or thuja can make a large tree although it has been more often used as hedging in gardens. It can reach to over 40m with branching stems. The biggest pine is the Monterey pine, also from California; it is a rapid grower, very wind-resistant and capable of making a huge trunk and massive branches, though often close to the ground, and height of over 30m and as much across are not unusual.

While most of the biggest trees are conifers from North America, there are no really huge deciduous trees from America except the tulip tree, which is normally seen as a young specimen in gardens but there are some really big trees in old estates and it is capable of growing to well over 30m, making a clean stem. It does best in the warmer parts on deep fertile well-drained soil. The London plane, which is a hybrid between an American species and the oriental plane, the latter capable of large size too, can make a large tree to 40m tall. Eucalyptus can make very tall trees, the largest potentially being the blue gum. However, this can suffer frost damage and is likely to be set back except in the milder coastal areas, where the biggest eucalyptus at well over 30m are seen. Monkey puzzle is native to Chile and can make a large tree here in good deep, moist but well-drained soil, making over 25m when suited.

Redwoods in Carlow.

Planting big trees

Choose a place where they are likely to be left undisturbed for possibly hundreds of years and allow them plenty of space to develop their full potential size. They can be planted alone or in a group, or with smaller ‘nurse’ trees. Single trees tend to become more wide than tall and if planted in a group, with thinning as space is needed, taller trees result. The soil needs to be good, although some stone and rock will not matter if the rock is not a solid barrier. Livestock must be fenced out at least 2m, or allowed to puddle the root area.

This week

Lawn

Moss is beginning to get the upper hand but lawn mosskiller can be used now. Moss will grow strongly in the coming months and eventually overcome the grass. Grass growth is tailing off and the grass will not be able to assert itself until spring. However, grass tends to grow a little over winter and an occasional mowing will keep it neat, but do not mow if the soil is too wet.

Trees, shrubs and roses

Planting of bare-root deciduous trees, hedging and shrubs can continue in good weather. Do not plant into heavy wet ground or into planting holes that fill with water, because the wet conditions cause the roots to rot. All kinds of pot-grown trees and shrubs can also be planted. Check that young trees are securely staked, wind-rocking can damage, and even kill, young trees that are not yet wind-firm.

Fruit, vegetables and herbs

Plant new fruit trees and bushes. Dig over vegetable ground, removing old crops. Control weeds over areas of ground that will be dug over later. Spread compost and rotted manure before digging it in. Pick the last of the outdoor tomatoes if not already done. Plant garlic if you have well-drained soil.

Flowers

Spring bulbs should be planted by now but if not, do not delay further. Tulips react better to later planting. Bedding plants for spring colour should be put in now, if not already done. Lift dahlias, begonias and gladiolus in frosty localities to prevent damage, or cover them with soil in milder areas.

Greenhouse and house plants

All tender plants should be brought under cover by now. Remove all debris and dead plants and ventilate occasionally. Water very little to reduce the risk of grey mould disease. Set up a greenhouse frost protection heater to protect tender plants, such as geraniums or fuchsias.

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