How to Grow and Care for White Spruce

The white spruce is a native to the northern reaches of North America, where it enjoys regular cool temperatures and moist conditions that keep it a bright green throughout the year.

People throughout the country do not often get to enjoy these towering evergreens because of climate limitations. Horticulturalists, though, have created dozens cultivars of Pilea glauca that have allowed people to use the species in their landscapes, from micro to weeping—you won't be disappointed.

If you are among the lucky that can grow a white spruce in their native area, caring for them isn't particularly difficult.

White Spruce Care

Here are the main care requirements for growing a White Spruce tree:

• Plant in well-draining soil.
• Ensure your climate is suitable.
• Provide Plenty of moisture.
• Place in an area that receives full sun.

Planting

The planting details will depend on the cultivar you are planting, but for a wild-type white spruce, you will want to give your tree plenty of space to grow and room for air to flow around the tree on all sides. Try to give a 10-foot buffer from the center of the tree to accommodate the maximum possible mature spread of the tree.

Light

A white spruce will grow and perform its best when planted in full sun. The species can also manage in partial shade without a noticeable impact. Certain cultivars will perform better in certain conditions, which should be noted before you purchase one.

Soil

Other than the ability of its soil to retain and drain moisture, the white spruce is very adaptable when it comes to soil. Unlike some conifers, it is not fussy regarding pH and soil consistency.

Water

Water can be an issue for the white spruce in certain areas, especially those that can become too warm. Supplemental watering may be needed to keep your white spruce vigorous and attractive if you are in the southern ranges of its habitable zone or are experiencing long stretches of dry weather.

Temperature and Humidity

Possibly the biggest conditional concern of the white spruce, depending on the cultivar, temperature is everything for this northern native. This species loves cold weather; it thrives in frigid winters and cool summers and suffers in the heat. Keeping strict to its USDA hardiness zone recommendations of USDA 2 through 6 will guarantee your white spruce won't be harmed by the climate.

Be sure to look closely at the plant tags of cultivars, as these may differ from the species recommendations.

Fertilizer

The white spruce does not require any supplemental fertilizer.

Types of White Spruce

If you want a tree with many cultivars to explore, there may not be a better choice than the white spruce. Like many conifers, the white spruce has been cultivated into dozens, if not hundreds, of cultivars, allowing landscapers and home gardeners to choose from trees in all kinds of colors, sizes, forms, and growth rates.

Looking for a cultivar of white spruce can be confusing because they are often hidden behind the various common names for the species Picea glauca goes by—namely white spruce, Alberta spruce, skunk spruce, Canada spruce, cat spruce, and Porsild spruce. This is why botanical names are so important.

Below are just a few of the more common cultivars out there, but a search will find many more.

• Picea glauca 'Conica'is a growing dwarf variety that becomes conical over time.
• Picea glauca 'Pendula' is a weeping variety with a slow growth rate.
• Picea glauca 'Green Carpet' is a cultivar with blue-green needles and a flat growing habit.
• Picea glauca' Spruce Lane' is a very colorful cultivar with gray-green needles tipped in yellow. Cones are a vibrant red that fades to yellow at the end.

Pruning

There is no need to prune white spruce to shape or form it. It only needs maintenance pruning (removing dead, dying, and damaged branches). They will grow as intended and will only need to be pruned if branches are creating a hazard.

Propagating White Spruce

White spruce is most easily propagated by cutting or grown from seed. While it is possible to propagate through grafting, this is difficult, so using cuttings and seeds is the most common route for the typical home gardener to propagate the white spruce.

Here's how to propagate white spruce using cuttings, a process best done in winter or early spring:

1. Choose a healthy and green branch; use only established growth.
2. Separate the cutting from the main branch with sharp shears. Look for a "node" and lively growth on a branch, then cut between the two.
3. Scrape the cutting about an inch from the bottom to remove some bark, then dip the exposed piece in rooting hormone.
4. Place the cut end of the branch in a pot filled with damp peat moss and tamp the medium down thoroughly around the base. Use pots at least 5 inches deep and with holes for drainage to allow for better root growth. The cuttings might take up to 6 months to develop their root systems.
5. When there is ample root growth, repot to larger pots.
   

Overwintering

The white spruce will thrive at very low temperatures, and no overwintering is needed. Immature trees will often do better if a thin layer of mulch is placed around their base to help insult their developing roots; mature trees will not need such protection.

Common Pests & Plant Diseases

Relatively disease-resistant trees when in the right conditions, white spruce can become susceptible to plant diseases when exposed to drought or higher than usual temperatures.

Two common fungal diseases that can arise in these conditions are rhizosphaera needle cast (the most common white spruce disease) and cytospora canker. Both diseases share the same symptoms: needles will turn brown in late winter to early spring and begin to drop by summer. Usually, these diseases are not fatal but can be very unsightly.

Ensure plenty of water during droughts to help stem these pathogens; be sure you're watering the soil around the base of the tree without allowing a backsplash onto the needles. Planting with an appropriate space between trees will also defend against both diseases, as proper airflow will allow needles to dry between watering.

As far as insects go, the wild-type white spruce is very good at holding its own against pests when mature. Cultivars can be more prone to insect damage, so you must take more care and inspect them for signs of pests more often. The most common pests you will find are spider mites and bagworms. Botanical oils and insecticidal soaps can help with the problem.

From: thespruce