{"id":611953606982,"date":"2025-10-16T16:41:55","date_gmt":"2025-10-16T16:41:55","guid":{"rendered":"https:\/\/blogs.ashridgetrees.co.uk\/blogs\/uncategorized\/lavender-diseases-there-really-are-some\/"},"modified":"2026-04-21T08:42:23","modified_gmt":"2026-04-21T08:42:23","slug":"lavender-diseases-there-really-are-some","status":"publish","type":"post","link":"https:\/\/blogs.ashridgetrees.co.uk\/blogs\/garden-plants\/lavender-diseases-there-really-are-some\/","title":{"rendered":"Lavender Diseases and Pests \u2014 Common Problems and How to Treat Them"},"content":{"rendered":"

Does Lavender Get Diseases and Pests?<\/h2>\n\n

Lavender has an undeserved reputation for being disease-free. It is more resistant than most garden plants \u2014 its aromatic oils do provide some protection \u2014 but it is not immune. The four main problems we see at the nursery are Alfalfa Mosaic Virus, Lavender Shab disease, sap-sucking insects (particularly froghopper nymphs), and root rot from poor drainage. Of these, root rot from wet soil is by far the most common cause of lavender death in UK gardens.<\/p>\n\n

What Is Alfalfa Mosaic Virus in Lavender?<\/h2>\n

Alfalfa Mosaic Virus causes yellow and pale green patches on lavender leaves, and is spread by aphids. There is no cure. If you see it, remove and destroy affected plants promptly \u2014 do not compost them. The good news is that AMV is relatively uncommon in lavender compared to the other problems below, and a healthy, well-sited plant is less likely to be affected.<\/p>\n\n

What Is Lavender Shab Disease?<\/h2>\n

Shab is a fungal disease that causes lavender stems to die back suddenly, turning grey and then brown. It typically strikes after the plant has been wounded \u2014 by heavy pruning at the wrong time, by frost damage on soft new growth, or by mechanical damage. Infected stems should be cut back to healthy wood and the pruned material disposed of (not composted). Avoiding late-autumn pruning, and always cutting into green wood rather than bare wood, significantly reduces the risk.<\/p>\n\n

Do Capsid Bugs and Froghoppers Affect Lavender?<\/h2>\n

Green capsid bugs distort new growth and cause puckered, misshapen leaves at shoot tips. Froghopper nymphs surround themselves in a mass of white froth (the “cuckoo spit” you see on plants in early summer) and feed on plant sap. Neither pest is usually serious enough to threaten a healthy plant, though heavy infestations can affect growth and flower production. Remove cuckoo spit by hand or with a jet of water; capsid bugs are harder to control but populations are usually kept in check by natural predators.<\/p>\n\n

What Is Root Rot and How Do I Prevent It?<\/h2>\n

This is the big one. Poor drainage kills more lavender in the UK than everything else combined. Lavender evolved in dry, free-draining Mediterranean soils. When its roots sit in wet, cold, poorly-drained soil through a British winter, the roots rot and the plant dies \u2014 often suddenly, appearing to collapse for no obvious reason once the soil warms in spring.<\/p>\n\n

The symptoms: the plant dies back suddenly after winter or a wet spell, often in a sector or all at once. Pull gently on a stem \u2014 it will detach easily at the base with dark, rotten roots. If the base of the plant is healthy but one or two stems are dying back, that may be Shab; if the whole root ball is black and soft, that is root rot.<\/p>\n\n

The prevention is the same as the cure: drainage. Plant lavender in free-draining soil or on a slight slope, add grit to heavy soils, or grow in pots with plenty of drainage holes and a gritty, soil-based compost. In borderline situations, planting on a small mound a few inches above the surrounding soil level can make the difference between a plant that thrives and one that dies.<\/p>\n\n

There is no treatment for root rot. Remove and discard the plant (do not compost), improve drainage in the site, and replace with a new plant. If drainage genuinely cannot be improved, grow lavender in pots.<\/p>\n\n

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Related Lavender Guides<\/p>\n