Guava trees love California sunshine, but they get nervous when fall nights start to chill. A tree that looks perfectly healthy in October can lose tender new growth after just one cold snap.
The good news is that one simple fall habit can help your guava stay strong through winter. It takes less time than mowing the lawn, and it can make a real difference come spring.
1. Stop Feeding and Cut Back Watering to Harden Off New Growth
Picture a guava pushing out soft, bright green leaves in late October. It looks lovely, but that fresh growth is the first thing frost will burn.
The single best fall move is to stop fertilizing and slowly ease back on water so the tree can toughen up before cold nights arrive.
Guavas are tropical at heart, and young tissue can be damaged near 32 degrees F, while mature trees may handle a few degrees lower. Nitrogen fertilizer in fall tells the tree to keep growing, which leaves it with tender shoots right when inland valleys and foothill yards start dipping into the 30s.
Make your last feeding by late August or early September, then let the tree settle down.
Watering works the same way. Instead of keeping the soil soaking wet, let the top few inches dry between deep drinks, which fits nicely with California water rules too.
Do not let the tree go bone dry, though, since moist soil holds more daytime heat and can release a little warmth on chilly nights.
Finish with a 2 to 3 inch layer of mulch, kept a few inches away from the trunk. Hillside homeowners in fire zones may prefer gravel or a lighter mulch ring near the house.
Fun fact: strawberry guava and pineapple guava (feijoa) are tougher in cold than tropical guava, so this step matters most for Psidium guajava.