Prune blue spruce tree

Pruning evergreens

Evergreen refers to a group of plants that retain their foliage during winter. Most evergreens have a strong central branch leader, which requires little pruning except to control plant height, increase the density of branching, or to shear into special shapes.

Proper identification and growth habits are necessary before pruning or the natural shape and beauty of a plant can be destroyed. Evergreens can be grouped on the basis of whether they have whorled branches (pines, spruces, firs, and Douglas-fir) or random-branching patterns (yew, arborvitae, hemlock, cedar, and juniper). New growth extends from buds that were formed the previous year on the tips of twigs. However, a few random-branched species are capable of generating new growth on both old and new wood portions of the branch.

Prune all evergreens, except pine, before new growth starts in the spring or during the semidormant period in mid-summer. When pruning, follow the general branching pattern to maintain the natural shape. Remove dead, diseased, or broken branches anytime. When shearing, begin in late spring or early summer when new growth begins. This allows cuts to heal and new buds to form for next year. In most cases, selective pruning (one branch at a time) is better than shearing. Shearing creates a formal, geometric shape that looks out of place in a natural landscape and becomes more difficult to maintain as the plant increases in size. (Pruning paints are not necessary since pitch quickly seals the pruning wound.)

Occasionally, an evergreen may lose its leader. Sometimes a new leader develops from a latent (dormant) bud, or one of the uppermost branches will dominate and become the new leader. If no leader develops naturally, tie one of the topmost branches upright, training it to become the new leader. Shorten surrounding lateral branches to reduce competition.

WHORL-BRANCHED EVERGREENS

Pines (Pinus) Pine needles are arranged in clusters or bundles, which are fastened to a twig in a sheath. The number of needles in a cluster varies from species to species, but usually they are in bundles of two, three, or five. Most pines produce their buds on the terminal tips of their shoots and not along the stems. This results in one flush of growth per year. New shoots are called candles.

  • Prune pines in the spring as new growth emerges.
  • To produce a compact, uniform plant or to maintain a plant shape, pinch one-third to one-half of each candle when it expands in the spring. Do not prune back into woody stems; new growth will not develop from these areas. Shearing is not recommended.
  • When older pines are overgrown, the only option usually is to remove an entire branch.

Spruce (Picea)

Spruces have individual, angled needles with brown pegs at the base of each needle. The pegs remain on the twig after the needles drop, resulting in a rough twig. Buds are scattered along the twigs of the newest growth. Cones are long and pendulous. Although spruces need very little pruning, bottom branches may die with age and can be removed.

  • For a formal shape, prune new growth in the spring. Shear in late spring, after new growth has expanded.
  • To reduce the size of a branch, cut back to a lateral branch or a visible dormant bud. This can be done at any time.
  • To repair a broken leader, cut off the broken branch and tie one of the shorter side shoots upright onto a splint, training it to become the new leader. Remove the tie after one year. If two leaders develop, remove the weaker one.

Firs (Abies)

  • Prune firs as you would a spruce. Douglas-Fir (Pseudotsuga)

Although not a true fir, the overall form is similar to spruces and firs. Douglas-fir has flat needles and smooth twigs on pendulous branches. Cones have distinctive bracts extending beyond the scales.

  • Prune as you would a spruce.

RANDOM-BRANCHED EVERGREENS

Arborvitae (Thuja) The needles of arborvitae are flat, frond-like fans. Cones are distinct, half-inch clusters. Arborvitae comes in many different forms and sizes that should be maintained when pruning. Arborvitae will withstand heavy pruning and shearing because new branches develop from concealed buds in the branch crotches. Prune in early spring or mid-summer.

  • When heavy pruning is necessary, prune before new growth begins in early spring so that new growth conceals pruning cuts.
  • To lower the height (no more than 20 percent) of a plant, cut back to a lower branch crotch, making cuts only into live wood. To regain the natural shape of the plant, balance lower limbs by lightly pruning branch tips.
  • Older arborvitae growing in shade will develop a dead zone that is incapable of regenerating new growth. Do not prune into this area.
  • Oriental arborvitae (Thuja orientalis) is slow growing and responds best to shearing new growth only.

Junipers (Juniperus)

This diverse group of plants includes spreading, upright, pyramidal, and creeping habits. Junipers have two types of needles, one scalelike and the other prickly and sharp. Both types are often seen on the same plant. Fruit is a distinct, light blue, berry-like cone. All junipers develop a dead zone in the center of the plant because of insufficient light. New growth will not develop from this area unless green needles remain. Severe pruning is not recommended.

  • To correct the shape, prune before new growth starts in the spring; lightly prune side branches to reduce their size and to bring the plant back into scale.
  • Prune spreading and creeping junipers by selectively cutting back to vigorous, lateral side branches. Do not shear in a formal manner.
  • Overgrown specimens can be lowered up to 20 percent, but cuts must be above the dead zone.
  • When shearing junipers, care should be taken to leave some new growth on the plant to avoid pruning back into the dead zone. Shearing should take place in the spring when plants are actively growing.

Yews (Taxus)

Needles are glossy, dark green, and arranged spirally in pairs along erect stems. Fruit is a fleshy, red berry. Yews range from spreading ground covers to various-sized trees and shrubs. Yews are slow-growing, long-lived plants, which produce two flushes of growth per year. New growth will develop on old wood, making yews very tolerant of heavy pruning or shearing.

  • To maintain size, prune in late winter or early spring, before new growth begins. Prune again in mid-June.
  • Annual shearing should be done after new growth has expanded. Follow-up shearing should continue throughout the growing season. To avoid stimulating new growth late in the season (thus preventing winter injury), do not shear yews after August.

Hemlocks (Tsuga)

On hemlocks, small, flat, dark greenneedles are arranged spirally around the stem. Cones are small and pendulous. Hemlock grows as a tall tree, but can be pruned or sheared as a hedge.

  • Prune as you would a yew.

Cutting Back Dwarf Spruce: How To Prune Dwarf Spruce Trees

Dwarf spruce trees, despite their name, do not stay especially small. They don’t reach heights of several stories like their cousins, but they will easily reach 8 feet (2.5 m.), which is more than some homeowners and gardeners bargain for when they plant them. Whether you’re looking to cut back a large dwarf spruce or just keep one nicely shaped, you need to do a little bit of dwarf spruce pruning. Keep reading to learn more about how to prune dwarf spruce trees.

Cutting Back Dwarf Spruce Trees

Can dwarf spruce trees be pruned? That really depends upon what you’re trying to do. If you just want to do some shaping and encouraging bushier growth, then pruning should be easy and successful. If you’re looking to cut back a large or overgrown tree to a more manageable size, however, then you might be out of luck.

Vigorous Dwarf Spruce Pruning

If your dwarf spruce tree is larger than you’d hoped, and you’re trying to cut it down to size, you will probably run into some problems. This is because dwarf spruces only have green needles at the ends of their branches. Much of the interior of the tree is what’s called a dead zone, a space of brown or nonexistent needles.

This is perfectly natural and healthy, but it’s bad news for pruning. If you prune a branch into this dead zone, it will not grow new needles, and you’ll be left with a hole in your tree. If you want to prune your dwarf spruce tree back smaller than this dead zone, the best thing you can do is remove the tree and simply replace it with a smaller tree.

How to Prune Dwarf Spruce Trees

If you just want to shape your dwarf spruce, or if your tree is young and you want to trim it to keep it small, then you can prune with a good amount of success.

Taking care not to cut into the dead zone, cut back any branches that extend beyond the tree’s conical shape. Remove ½ to 1 inch (up to 2.5 cm.) of growth at the tips of the lateral branches (branches that grow out of the trunk). Remove 2 to 3 inches (5-8 cm.) of growth from the ends of side branches (the ones that grow out of the lateral branches). This will encourage thicker, lush growth.

If you have any bare spots, lightly trim every branch around it to encourage new growth to fill it in.

Fielding Questions: Dwarf Colorado spruce no longer dwarf

Q: Our dwarf Colorado blue spruce is no longer dwarf. It’s nearly five feet tall and probably just as wide. Can it be trimmed? If so, when is the best time to do this? – Shirley Smedshammer, Fargo.

A: There are several dwarf varieties of Colorado blue spruce (Picea pungens.) They stay relatively short compared to the 40-feet-tall parent, only growing a few inches every year. But the dwarf varieties can still become a large, mound-shaped plant, eventually reaching a height of 5 to 6 feet. Several newer varieties remain shorter.

Your dwarf spruce might be close to its maximum height. To be sure it gets no taller, its dimensions can be held at their current size by “mold-and-hold” type pruning, in which you prune the outer tips each year in May or June. But if you want to decrease the spruce’s current size, it’s important to limit pruning to the vicinity of healthy needles. If cuts are made back to bare twigs, growth will not usually sprout. The spruce can be shortened somewhat, just don’t go back too far into old wood.

Q: My honey crisp apple tree started to produce well last summer. The problem is that the apples looked nice on the outside but had brown streaks on the inside. Are these edible and what can I do to prevent it this year? – Marlene Olson, Fargo.

A: Brown streaking inside apple fruits is usually caused by the apple maggot. Adult flies emerge from the soil in late June or early July. Females puncture developing fruit to lay eggs, which often leaves a tiny dimple. The eggs hatch into small wormlike maggots, which tunnel through the fruit as they eat, causing brown streaks. By late summer, maggots exit the apples, enter the ground to overwinter, and the cycle starts again the next year. Fruits are safe to eat, and the maggots have usually left by the time apples are ripe.

To control apple maggots, spray trees with Sevin or spinosad insecticides beginning about June 25, and continuing at seven- to 10-day intervals until mid-August. Sanitation is important. Remove all fallen apples immediately to prevent maggots from entering the soil for future infections.

There’s one other problem that Honeycrisp growers encounter causing internal brown spots. It’s called bitter pit, and is more common on younger, newly fruiting Honeycrisp trees. It’s a physiological disorder caused by interactions of growth conditions, fertility and vigor. Commercial Honeycrisp growers often apply calcium sprays. But if the internal browning is in railroad-like streaks, apple maggot is the more common problem.

Q: Is it possible to start Korean lilacs from the suckers growing up around the shrub? – Shirley Smedshammer, Fargo.

A: Suckers don’t pop up out of the ground around the perimeter of dwarf Korean lilac the way they do in old-fashioned common lilacs. But sometimes there are sucker shoots close to the base of Korean lilacs that can be separated from the mother plant, as long as the sucker sprout has its own little root system. It might be necessary to cut adjoining woody tissue to separate the sucker. Early spring is best. Take extra care to get moist soil immediately around the roots if doing the operation now, when lilacs are in full leaf.

If you have a gardening or lawn care question, email Don Kinzler at [email protected] All questions will be answered, and those with broad appeal may be published, so please include your name, city and state for appropriate advice.

How to Trim a Colorado Blue Spruce

A Colorado Blue Spruce is somewhat forgiving when it comes to being trimmed, but if you don’t follow the appropriate guidelines, you could end up with a shaggy tree that looks more like a hedge gone berserk than it does a conifer. Of course, you may prefer a fuzzy look to your blue spruce. While the Colorado Blue Spruce can technically be trimmed at any time of the year, trim in the winter or early spring for the best results.

Remove all dead wood and branches. Cut all dead and dying branches back to within 1 inch of the trunk. You will find a swelling (a node) where the branch attaches to the trunk; make your cut just beyond this node, leaving the node on the tree. Trim large branches by making a 1/2 inch deep cut on the underside of the branch at the point where you want the branch cut. Then cut all the way through the branch, cutting from the top side of the branch, about 3 inches beyond the first underside cut you made. In this way the branch can break off cleanly without tearing the bark as you near the completion of your cut. Once the major part of the branch has broken off, cut off the 3-inch stub where you made your first cut.

Review the looks of your tree and cut off branches (following the directions in Step 1) which do not contribute to the overall look you desire. Remember, cutting the ends of a branch will cause your Colorado Blue Spruce to grow “fuzzy” branch ends where you make your cuts.

Do not top a Colorado Blue Spruce. Trim off approximately every third branch if you wish to slow the growth of your spruce and keep it from getting too tall.

Cut lower branches as per the directions in Step 1 to facilitate walking and mowing under the tree. Cut branches that cross each other, or which are rubbing together.

Trimming a Blue Spruce tree

Hello,
You may not be able to remove branches up to the height of 10-12 feet. In order to maintain structural integrity of the tree, at least 1/2 of the foliage needs to be maintained in the bottom two-thirds of the tree (figure 18 in document listed below). If following this strategy does not give enough clearance, consider whether required clearance can be achieved with removal and reduction cuts out along the branch rather than removing large branches entirely (as in Figure 19). Ideally, prune out branches less than 4 inches in diameter.
As described in CSU GardenNotes 615 (click on link to display entire document with diagrams)

Raising Raising is the removal of lower branches to provide clearance for people, traffic, buildings, or a view. When removing lower branches, maintain at least one-half of the foliage in the lower two-thirds of the tree. The lowest branch should originate in the bottom one-third of the tree’s height (live crown ratio). Figure 18. When removing lower branches, maintain at least one-half of the foliage in the bottom two-thirds of the tree. The lowest branch should originate in the lower one-third of the tree. Raising should be part of the tree’s structural training while young. Ideally raising would be done before branches to be removed exceed a two-inch diameter. The potential for decay is high when the branch removed is larger than four inches or when a two-inch and larger branch is greater than half the diameter of the adjacent trunk (no branch collar to suppress decay). On many trees, lower branches make-up a significant portion of the tree’s entire canopy and cannot be removed without significantly influencing tree health and appearance. When the branch to be removed is larger than two inches, consider other alternatives. Can the clearance required be achieved with removal and reduction cuts out along the branch rather than removing the entire branch? Leaving some small diameter branches on the lower trunk for a year helps close pruning wounds and lessens the potential for trunk cracking. Figure 19. In raising branches on maturing trees, consider if required clearance can be achieved with removal and reduction cuts out along the branch rather than removing large branches entirely. Excessive removal of lower branches increases the potential for tree failure by decreasing trunk taper, causing trunk cracks and decay, and transferring weight to the top.
If, as a last resort, you need to consider replacing this beautiful old tree, consider replacing it with a dwarf spruce variety such as R.H. Montgomery, Sester or Baby Blue Eyes. http://www.ext.colostate.edu/ptlk/1704.html lists other options. Choose the variety based on the mature size of the tree.
Best wishes,

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