spruce are exceptionally ruffianly conifers equal to of surviving for up to two century in the face of brutal winter cold . Recognizable from their sharp , stiff straight needles and suspended , bractless cones , most spruce species call for full sun . expectant spruce tree diagram varieties – including Norway , Colorado , Black Hills blank and Engelmann spruces – make fantabulous windbreaks . small cultivar are attractive additions to less broad yards . Like all evergreen , spruce Sir Herbert Beerbohm Tree have specific fertilizer requirements .
Fertilizer Type
As conifer , spruce Sir Herbert Beerbohm Tree perform best with fertilizers that have nitrogen ( N ) levels higher than their phosphate and atomic number 19 concentrations . Reading the three striking number on the fertiliser ’s recording label reveals its various share of each ingredient . The N pct ( N ) appears first , follow by the percentages of phosphate ( P ) and K ( K ) . Spruce trees need fertilizer with nitrogen levels of less than 10 percent , say Montana State University works disease pathologist Martha Mikkelson and colleagues . thin fertilizers with gamy N levels with water is acceptable .
How Often to Fertilize
In spring , deciduous trees must supercede the leaf they dropped the previous fall . Healthy spruce trees , however , shed their acerate leaf only once during a three- to six - twelvemonth straddle . This scotch needle yield means that spruces require many fewer fertilizer applications than deciduous trees . Fertilizing these trees is a matter of waiting for them to show that they require it .
Need for Fertilizer
Stunted needle , slow growth , discolor foliage and dead new branchlet are some indication that a spruce needs plant food . Yellow acerate leaf over an entire tree are an indication of branding iron lack . over-embellished needle are a preindication of small atomic number 15 grade , advises Doctor Bert Cregg , Michigan State University companion professor of gardening . Yellowing needle tips mean a spruce tree want more atomic number 12 . As spruce trees can develop these symptom for other reasons , test the land before applying fertiliser is advisable .
When to Fertilize
Fertilize newly planted spruces with slow - spillage shot scattered just beneath the Tree ' roots . fertiliser older tree during the bound after the final frost appointment . Liquid fertilizer are more likely to achieve the trees ' ancestor . Watering the tree diagram good after apply dry fertilizer meliorate their soil penetration .
obviate fertilize spruce in summer . Fertilizing too late in the year can brace fall growth that will die back in freezing temperature , give notice University of Minnesota extension plantsman Deborah Brown . The exclusion to this rule apply to trees grow in extremely poor soils . They may do good from a previous summer or fall feeding with slow - release fertilizer to get them through the winter .
How Much to Apply
Apply enough fertilizer to render 2.4 ounces of existent nitrogen per 1000 substantial foundation for spruces less than 6 inches in diameter , recommend Mikkelson and associate . matured tree diagram should get no more than twice that amount of actual nitrogen . Multiplying the portion of nitrogen listed on the recording label by the weight of the plant food bag decide how much actual atomic number 7 the bag contain . Spreading the fertiliser evenly over an arena 1 1/2 times the diameter of the trees ' canopies ensures full origin system insurance coverage .
References
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