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By John | January 20, 2008
Algae, moss and lichens on trees and paths
Algae, moss and lichens are non-parasitic organisms that use structures as growth supports. They do not harm plants and can make interesting features, preferring damp, still areas. However, they can make paths slippery, so control is sometimes necessary. Gelatinous algae are dark jelly-like growths that often appear in damper, cooler weather on paths and areas of tarmac.
On plants
Algae, moss and lichens often grow on congested, non-vigorous plants and so are unjustly blamed for the plant’s poor condition. However, they can also appear on vigorous new plants in humid areas and are fairly common in western districts. They frequently colonise the sheltered side of dense evergreen hedges, such as holly (Ilex) and yew (Taxus).
Control: Prune plants to encourage better air flow, and top dress in spring with a general-purpose fertiliser to improve vigour.
Chemical control: There are no chemicals available to control these growths on trees.
On paths
Growth often appears in sheltered areas overhung by plants.
Control: Prune overhanding plants to improve air flow. Regular mechanical removal of moss, algae and lichens using a pressure washer or stiff broom can be effective.
Chemical control: Apply products such as Finalsan Moss & Algae Killer (active ingredient – pelargonic acid). This is non-persistent and so requires repeat applications. Patio and path cleaners also have some effect. Do not use lawn mosskillers as they stain easily.
Topics: Flora & Fauna |
