We had beautiful hostas for two years under our shade trees. For the most part, they are now nonexistent – the few that continue to come up have stunted leaves. I’ve wondered if they are intolerant of the heat, since I’m at the warmest end of the recommended planting zones (zone 10)? -BJ

It doesn’t sound like a problem of summer heat intolerance, particularly since you grew them beautifully for two years. Hostas normally go dormant during a heat wave – they just sit there and wait it out (like the rest of us). They can be sensitive to the sun, however, which is evident if the leaves look faded, burned, or are deteriorating from the edges inward. For your shade-tree hostas, your problem might be:

• Critter damage. Meadow mice and voles love to munch on hosta roots and stems, which can stunt growth.
• Hosta Virus X. This virus at first creates a mottled pattern in the leaf colors (often mistakenly purchased as a new variety) and can result in stunted leaves that look puckered or twisted.
• Other disease, although the primary diseases that affect hostas – crown rot and foliar nematodes, for instance – usually result in visible leaf damage and quick, tragic plant death, which is not quite what you’re experiencing.
• Unusually warm winters. Hostas require about 6 weeks of cold weather for winter dormancy, including several weeks between 30-35 degrees F.
• Damage by surprise late-spring freezes.