How to Grow a Tamarack Tree

A Tamarack tree that has turned yellow in the fall.

Robbie Gorr/Getty Images

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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 in used 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 to have its needles re-emerge 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 landscape designer's needs.

Common Name Tamarack
Botanical Name Larix laricina
Family Name Pinaceae
 Plant Type Deciduous Conifer
 Mature Size 40 to 80 ft. tall, 15 to 30 ft. wide
 Sun Exposure Full sun
 Soil Type Moist, organic-rich
 Soil pH Acidic
 Bloom Time Non-flowering
 Flower Color Non-flowering 
 Hardiness Zones 2-5, USDA
 Native Area Northern North America

Tamarack Care

Tamarack trees do not require a ton of work, but they can be a bit fussy and have a few pests that you will need to look out for. If you give a good bit of thought before planting your tamarack, you can avoid many of the problems ahead. When you decide where to plant your tree, realize that this species does not like competition; it will require a good amount of space between it and any other trees to thrive. In nature, tamaracks grow in wet areas such as bogs or swamps. Planting it in an area that gets moisture that replicates these conditions will be best for the tree. This is less important than providing ample sun but will cut down on your supplemental watering needs.

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 ensure it gets 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, humid weather that comes outside of USDA zones 2-5. For those that 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 doing its wonders.

Types of Tamarack Tree

If you love the tamarack but don't love the space required to have one, there are some options out there for you. The options are many and will accommodate you if your yard is narrow or you don't have much room at all. Here are a few popular cultivars of tamarack to give you some ideas, but there are always new selections being cultivated.

  • Larix laricina 'Northern Torch' is a very dense globose dwarf form of the species. It will only grow to a height of five feet after 10 years.
  • Larix laricina 'Bear Swamp' is a remarkable low spreading dwarf variety that will get wider than it is tall with pleasing 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.
  • Larix laricina 'Nash Pendula' is a well-known cultivar with bright green foliage and a unique open pendulous form that reaches 10 feet after 10 years.

Common Pests and Plant Diseases

Though other pests may harrass 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.