If the leaves of your spruce, which were previously shimmering blue, take 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 triggers for brown needles on a blue spruce.
Why does my blue spruce have brown needles?
Brown needles on a blue spruce can be caused by care errors (e.g. B. drought, road s alt, lack of nutrients), diseases (spruce needle rust, spruce needle redness, spruce needle scab) or pests (book printer, spruce gall louse). A precise cause analysis and adapted measures help to support the tree.
Failures in care cause needles to brown
Planting your blue spruce in soil with a pH between 6.5 and 7.5 will prevent one of the most common causes of brown needles. However, if the following care errors occur, your Norway spruce will not be spared from the damage:
- Drought: Water the evergreen blue spruce regularly all year round, including in winter when it is dry and cold
- Sprinkling s alt: Never apply road s alt in the catchment area of the roots
- Nutrient deficiency: Fertilize the conifer in the bed and pot every 4 weeks from March to September with leaf compost
As a conifer, the blue spruce depends on an adequate supply of magnesium. If there is a deficiency of this special nutrient, the needles initially turn yellow and later brown. The deficiency can be remedied with the administration of Epsom s alt.
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)
- Spruce needle red (Tiarosporella parca)
- Spruce needle scab (Lirula macrospora)
Although these are different fungal pathogens, they ultimately cause the same damage. In the absence of effective control agents for home and allotment gardens, careful care is the only effective form of prevention.
These pests cause brown needles
There are primarily 2 types of insects that attack your Norway spruce to such an extent that the needles turn brown. If you notice 4-5 mm small, brown, roller-shaped beetles, you are dealing with book printers (Ips typographus). However, if the branches are covered with yellowish, pineapple-like galls in May and June, the spruce gall louse (Sacchiphantes viridis) has struck.
Tip
When analyzing the causes, it is often overlooked in the heat of the moment that brown needles can be due to a natural vegetation cycle. Although the blue spruce thrives as an evergreen conifer, it still replaces its needles every 7 years at the latest. During this process the needles turn brown before they are shed.
