fertilizing spruce trees

Asked June 29, 2018, 5:28 PM EDT

Hello Just wondering about using evergreen fertilizer spikes for Black Hills Spruce that are about 15 feet tall and were planted last year in early summer. We are in Woodbury Minnesota and have heavy clay soil. The trees seem to be in good health, we used the spikes in early May and wondering when we should do it again. Should we do it now into July so as not to cause new growth to late in the season so it can harden for winter or as the box says in spring and again late fall. We are also having a Kelp ground injection in mid summer from Sava Tree which is suppose to be more of a vitamin type application than fertilizer. Thanks

Washington County Minnesota

1 Response

The need for fertilization on a new tree depends on what you want the tree to do and if there are any disease/insect pressures in the area. More nitrogen, more insect pest problems...potentially. Adding nutrients via the spikes and/or the kelp soil injection should be enough, actually, should be plenty. Clay soils are nutrient-rich in the first place. However, if you are trying to block a nasty view or wind, then adding nitrogen is okay. Small amounts. Do it when there's active growth, which if you're irrigating their lawn, would be anytime this summer and early autumn. Fertilizer spikes will not cause the plants to skip acclimation for winter (it's triggered by day light length), and unless you use an extreme number of spikes, there will be no harm.