Blue Spruce & Needle Cast


One of the most glaring home landscape issues in the Midwest is the prevalence of declining and dead Colorado Blue Spruce (Picea pungens). The causal agent of the disease (needle cast) is several species of a fungus (Rhizosphaera)--other species, especially White Spruce (P. glauca), Oriental Spruce (P. orientalis), also are susceptible. The characteristic needle death and loss will start at the bottom, within the canopy, on the north as well as any shaded portions. There was a time, now long gone, when these spruce did not present this condition here. Unfortunately, now, the disease is inevitable even if effort is made to suppress the disease with multiple and well-timed (spring) spraying with fungicide. In fact, the condition has become such a negative issue, most garden centers and wholesalers smartly avoid offering the potentially beautiful and formerly longer-lived Colorado Blue. About ten-years is all one can expect now from a specimen, and probably less if not open grown and situated in full sun--most are not. The tree or dwarf shrubby cultivar may not be dead within a decade, but will look so progressively skanky and without hope of regenerating new needles, that one should do the right thing and remove it. Limbing-up can only mask the problem short-term. Rocky Mountain Juniper (Juniperus scopulorum) is another beautiful blue conifer that cannot be grown here due to a disfiguring fungal disease -- phomopsis, caused by a different pathogen--but many foolishly try.

So, where does the fault lie (i.e., with the causal agent and the susceptible host OR the person who should have known better than to offer, recommend or buy the vulnerable plants)? Not sure about you, but I think (and counsel others) that it is best to avoid problems--prevention is always better. Blue spruce decline from needle cast is an obvious and long-known problem that could and should be avoided. The problem is made more likely and presents sooner when specimens are improperly located AND by failure to apply a fungicide, which should be done even before the decline occurs as the affected portion will not recover. I understand that the multitude of property owners and landscapers who persist in treating plants as furniture (i.e., seemingly abiotic and merely a matter of artistic complement) will be reticent to accept this advice. However, just because you want something not to be true does not make it any less likely to be so. Alas, this is tough for many to accept. Unfortunately, there is no pill to prevent or cure delusional thinking and ignorance.

GOOD NEWS: I love conifers and can tell you there are some wonderful blue or somewhat blue species and cultivars that are hardy in central Indiana and mostly disease free, but some of these are rarely offered at garden centers OR you may not choose or have suitable habitat. As I frequently tell people, just because it is your idea or an established practice DOES NOT mean it is a good idea or practice.

PS: I do not remember a year when conifers produced so many cones. Not certain why the mega (mast) production this year, but I have marveled at and spoken about it to many of my gardening friends and associates. Note that cones on most species are massed near the top; a reproductive advantage. Finally, know that the mast production may be indicative of stress and may portend decline or death of at least some specimens.

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