How to Grow and Care for a Tamarack Tree

One of the most beautiful trees in the far northern forests of North America is the colorful deciduous conifer (Larix laricina), commonly called the tamarack or American larch.

The tamarack is used in ornamental horticulture to add four-season interest to a landscape in colder regions. The species turns a dazzling yellow in the fall before dropping its needles to reveal attractive flaking bark in the winter months. Then, its needles re-emerge in a blue-green hue for the spring and summer. Every year those lovely falling needles create a fine mulch that is pleasing to the eye and completely sustainable.

One downside to the tamarack is that it may be too large to fit some people's properties. If you are worried about this, the solution is out there. With the popularity of dwarf conifers, more and more cultivars are being added to the trade on a yearly basis to meet the needs of landscape designers.

Tamarack Tree Care

Here are the main care requirements for growing a tamarack tree: 

• Plant the tree in full sun and rich, wet, acidic soil.
• Water the tree regularly until it is established.
• Mulch around the base to conserve soil moisture.
• Use only organic compost for fertilizer, or do not fertilize the tree at all.
• Watch out for pests.
  

Light

This species of tree requires full sun. Tamarack trees are completely intolerant of shade, so it's important to clear out competing trees or shrubs. Making sure that your tree can grow in direct sun should help to provide adequate spacing. Place it at least 15 feet from any other trees.

Soil

Wet, organic soil is best for Larix laricina. It is native to a type of bog called muskeg, which is comprised of peat. This rich wet acidic soil is preferred and will help your tree thrive, but as far as soil needs go, the tamarack is more adaptable here than it is for its sun requirements.

Water

Tamarack trees require some supplemental water, especially during periods of drought and when the tree is first establishing itself. It will not tolerate being overly dry, so keeping the soil beneath it moist is important. On initial planting, adding two to three inches of good organic mulch to the dripline will help retain moisture. After a few seasons, you won't need to add more mulch since the tree makes its own beautiful needle mulch.

During the first three years, it is important to give your tree water weekly. Follow the standard of 10 gallons per inch of trunk diameter measured by caliper at knee height. If the weather is really dry, increase the water to 15 gallons—the tamarack won't mind!

Temperature and Humidity

Sadly for folks south of USDA hardiness zone 5, the tamarack will not tolerate the warmer climate. The tree needs cool weather during the summers and can handle extreme colds during the winters. It just cannot tolerate the hot, dry, or humid weather that comes outside of USDA zones 2-5. For those who love the look of this beautiful tree but cannot afford to relocate far enough north, try the equally gorgeous golden larch (Pseudolarix amabilis).

Fertilizer

The tamarack is used to growing in the wild and will do fine without much supplemental fertilizer once established. It is always a good idea to take a cue from nature. Fertilizing immature trees with some organic compost for the first few seasons will give it a little boost, but after that let nature work its wonders.

Types of Tamarack Tree

If you love the tamarack tree but don’t have the space to grow the tall species, you can still plant the tree. Small tamarack cultivars have been bred that are good even for a small, narrow yard. Popular cultivars include these compact forms:

• ''Northern Torch' is a very dense globose dwarf form of the species. It will only grow to a height of 5 feet after 10 years.
• 'Bear Swamp' is a low-spreading dwarf variety that will get wider than it is tall, with greyish blue needles that are a striking contrast to the yellow needles of autumn. This cultivar only grows about 32 inches by 42 inches after 10 years.
• 'Nash Pendula' is a popular cultivar with bright green foliage and a unique, open, pendulous form that reaches 10 feet after 10 years.
• 'Ethan' is a compact cultivar reaching of 6 to 8 feet in height after 10 years so it is suitable for small yards.
• 'Deborah Waxman' is a small, upright cultivar with bluish-green needles that only grows to a height of 3 feet in ten years.

Pruning

Generally, the tree needs little pruning and looks best if left to grow naturally. But if there are branches that are crossing or poorly formed, prune them between the late fall and early spring when the tree has dropped its needles and it is dormant.

Propagating a Tamarack Tree

Propagating a tamarack tree either from seeds (the tree only produces a seed crop every 3 to 6 years) or from cuttings is a lengthy and involved process that is best left to nursery professionals. Most cultivars and dwarf varieties are propagated by grafting, which is also not easily feasible for home gardeners. 

Potting and Repotting a Tamarack Tree

Unless you are growing a dwarf variety, tamarack is too tall to be grown in a pot. Choose a large deep planter with adequate drainage and fill it with well-draining high-quality potting soil. Heavyweight planters work best as they are less likely to topple over. Terra-cotta works well because it wicks away extra moisture.

Keep in mind that although tamarack is a very hardy tree, containers expose the roots to the cold so you will need to winterize it. Insulate the roots by wrapping burlap or bubble wrap around the container, or creating a planting silo by placing the container in a second, larger container.

Repot the tree in a larger container with fresh potting mix when the root system has reached the sides of the container, or the roots grow out of the drainage holes.

Overwintering

Tamarack is well-adapted to harsh winters and does not need any winter protection.

Common Pests

Though other pests may harass your tamarack, nothing will deliver as much trouble for your tree as quickly as the larch casebearer and larch sawfly. These two insects can inflict major damage to the bark and branches on the tree by nibbling away at it. If the wounds are severe enough, they can be fatal.

There is no chemical treatment for the larch casebearer, but there are numerous biological controls. Luckily, casebearer damage is rarely fatal for a tree.

To treat the larch sawfly, you should pick off any larvae you see on your tree, being sure that it is actually that of the sawfly and not a beneficial insect. Then, to create the lowest impact, treat the tree with insecticidal soap or horticultural oil. You should reapply as needed.