| Hedera | Boeremia hedericola | Causes leaf spots and damage to petioles |
| Helleborus | Coniothyrium hellebori | Causes unsightly black leaf spots |
| Hyacinthoides | Uromyces hyacinthi | Rust of leaves |
| Hyacinthus | Alternaria hyacinthi | Causes leaf spots and damage to bulb scales |
| Hypericum | Melampsora hypericorum | Rust on leaves, found on wild and cultivated species of Hypericum |