How to Propagate Black Spruce (Picea mariana)

This guide is meant to teach you how to propagate Black Spruce (Picea mariana) and hopefully make it easier for you to sell them at your own nursery.

Hardiness Zone: 2 – 6

Soil Type: Acidic, mineral-rich loam, peat, or sand.

Water: Normal, prefers moist environment.

Exposure: Full sun to partial shade

Black Spruce (Picea mariana) is a coniferous tree hardy up to hardiness zone 2. It’s identifiable by its narrow peak and irregular look that forms periodic dense tufts.

Black spruce bark is dark and scaly, the needles are short, growing only up to 1.5cm.

The needles have more of a round shape, if you pluck one and pinch it between your thumb and index, you will be able to roll it.

Black Spruce is a dominant tree species in the boreal forest, often found growing in peat bogs and swamps.

They are valuable trees and often a top choice for reforestation in my area. As much for crown land as for small private tree plantations.

Commercial value

Spruce produces a lightweight but dense and heavy-duty material. The top commercial use for black spruce trees is the pulp and paper industry. Additionally, they are a prime choice for structural applications in the construction market.

There is also value in harvesting seeds, and growing seedlings to sell to nurseries and individuals.

Quebec, for example, has many government-subsidized tree nurseries that produce black spruce seedlings by the millions.

Wildlife Value

They’re a great tree that provides food and cover for many boreal forest mammals. For example, squirrels, chipmunks, mice, and voles regularly eat their spruce cone seeds.

Additionally, larger mammals such as snowshoe hares, white-tailed deer, and caribou like to eat what they can off spruces. Moose love to eat lichens growing on their bark.

Best Way to Propagate Black Spruce

Seed

One sure way to propagate black spruce is by planting its seeds. Spruce seeds are hidden inside their tightly shut cones, which are only released under certain conditions.

If you have black spruce stands near you, all you need to do is harvest the cones and place them under dry heat, at about 122F to watch them open.

Alternatively, you can order black spruce seeds online here at treeseeds.

Black Spruce Seed Germination

• Soak in water for 24 hours
• Add into a mix 50/50 potting soil sand mixture
• Wait 1-2 weeks for germination

Black spruce is fairly easy to germinate and has a high success rate even without pre-treatment.

Cuttings

One of the best ways to propagate black spruce is by taking cuttings. There are two different times of the season to take them, softwood cutting season and hardwood cutting season.

Very important: Take your cuttings only from young, healthy plants. Older trees lose their ability to regenerate over the years.

When you take hardwood cuttings from spruce, you want to cut them after the first few hard frosts in fall or early spring when birches and maples begin to well. Alternatively, black spruce cuttings during winter, while the tree is dormant, are also fine.

• First, take some hardwood cuttings off the main stem, really short at about 2-4 inches ea.
• Make sure the width of the cutting is not too thin, 1/4 inch width is fine, then cut or tear them with a heel*.
• Remove the needles from about half of the cutting.
• Wound the base of the cuttings with a vertial line on opposite sides, about 1 inch long.
• Dip in rooting hormones and then plant into your sandy propagation beds.
• Keep watering the rooting medium, sand shouldn’t be too wet but it should stay moist.
• Roots are slow and can take longer than 8 weeks to grow.
• For winter, no need to cover, the snow isolates very well.

First, when you take softwood cuttings for spruce, you wanna cut them about mid-summer when the tree is actively growing.

Simply said, the process is the same as the hardwood cuttings, except you need to keep in mind they are faster growing but more sensitive.

Because of their tenderness, softwood cuttings die much faster than hardwood cuttings. Moistures levels are much more important to keep in check when you root cuttings at this stage.

• Take your spruce softwood cuttings at 2 inches each with a heel if possible. 
• Wound them with a vertical line at the base.
• Water the tips, pat them dry then dip them in rooting hormone.
• Poke holes in your rooting medium
• Plant them, carefully not to remove the rooting hormones.
• Moisturize your rooting medium regularly.

Recommended rooting medium: Peat moss or sand with perlite mix.

All in all, black spruce softwood cuttings are slow to root and generally take 6-8 weeks.

There are three essential items that help optimize cutting success indoors:

• Heating Mats with Thermostat
• Vented Seedling Trays with Covers
• Full Spectrum LED Lights

I personally use all 3 of these and can attest to them.

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With this setup, you can set at least 6 trays per heating mat. The thermostat regulates perfect rooting and sprouting temperature and the lights have a timer.

Since I don’t have access to my tree nursery in the winter, I work with this little winter set up inside.

Got any questions or tricks to add? Don’t be shy to comment below and spark up a conversation!