If the previously shimmering blue foliage of your spruce takes on a dull brown tone, there is usually an urgent need for action. In order to help your Picea pungens, the cause of the damage must be known. This guide highlights the most common causes of brown needles on a blue spruce.

Brown needles are usually a sign of disease or poor care

Mistakes in care cause needles to turn brown

Planting your blue spruce in soil with a pH between 6.5 and 7.5 will already prevent one of the most common causes of brown needles. If, on the other hand, the following care errors occur, your spruce will not be spared from the damage:

  • Drought: Water the evergreen blue spruce regularly all year round, also in winter when it is dry and cold
  • Road salt: Never spread road salt in the catchment area of the roots
  • Nutrient deficiency: Fertilize the conifers in beds and pots with leaf compost every 4 weeks from March to September

As a conifer, the blue spruce is dependent on an adequate supply of magnesium. If there is a lack of this special nutrient, the needles first turn yellow and later brown. The deficiency can be remedied with the administration of Epsom salt.

These diseases cause brown needles

If care errors can be ruled out as the cause, these diseases come into focus as triggers for brown needles:

  • Spruce needle rust (Chrysomyxa)
  • Pine blush (Tiarosporella parca)
  • Spruce needle scab (Lirula macrospora)

Although they are different fungal pathogens, they ultimately cause the same damage. In the absence of effective control agents for home and garden plots, prudent care is the only effective form of prevention.

These pests produce brown needles

There are mainly 2 types of insects that abuse your spruce to such an extent that the needles turn brown. If you notice 4-5 mm small, brown, cylindrical beetles, you are dealing with book printers (Ips typographus). If, on the other hand, the branches are covered with yellowish, pineapple-like galls in May and June, the spruce gall aphid (Sacchiphantes viridis) has struck.

tips

As part of a root cause analysis, it is often overlooked in the heat of the moment that brown needles can be traced back to a natural vegetation cycle. Although the blue spruce thrives as an evergreen conifer, it changes its needles every 7 years at the latest. During this process, the needles turn brown before being shed.

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Trees