Troubleshooting
Palo Alto Sweetgum problems — and how to fix them
Palo Alto Sweetgum (Liquidambar styraciflua 'Palo Alto') is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Iron/manganese chlorosis on alkaline soils
Yellowing between leaf veins (interveinal chlorosis) on alkaline or chalk soils is the most common problem. Correct by acidifying the soil with sulfur or applying chelated iron/manganese foliar feeds. Prevention is easier than cure — always plant on acidic substrates.
Spiny gumball fruit litter
Mature trees produce abundant spiny seed balls that fall and carpet the ground below, creating a hazard for bare feet and pets. 'Palo Alto' is not fruitless; consider this before planting over paths or lawn areas. Regular raking in autumn is required.
Sweetgum scale (Diaspidiotus liquidambaris)
Armored scale insects can colonise bark and twigs, causing dieback of smaller branches in severe infestations. Control with horticultural oil applied in late winter or early spring before bud break. Healthy, vigorous trees are generally resistant.
Prevent palo alto sweetgum problems before they start
Most palo alto sweetgum issues are care-mismatch, not bad luck. Dial in the basics:
Palo Alto Sweetgum problems — FAQ
Why is my palo alto sweetgum iron/manganese chlorosis on alkaline soils?
Yellowing between leaf veins (interveinal chlorosis) on alkaline or chalk soils is the most common problem. Correct by acidifying the soil with sulfur or applying chelated iron/manganese foliar feeds. Prevention is easier than cure — always plant on acidic substrates.
Why is my palo alto sweetgum spiny gumball fruit litter?
Mature trees produce abundant spiny seed balls that fall and carpet the ground below, creating a hazard for bare feet and pets. 'Palo Alto' is not fruitless; consider this before planting over paths or lawn areas. Regular raking in autumn is required.
Why is my palo alto sweetgum sweetgum scale (diaspidiotus liquidambaris)?
Armored scale insects can colonise bark and twigs, causing dieback of smaller branches in severe infestations. Control with horticultural oil applied in late winter or early spring before bud break. Healthy, vigorous trees are generally resistant.