Quick, go outside your house and take a quick look around your garden. Do you see anything that looks like this?
This is a classic example of plants being planted in the wrong place. These cast iron plants (Aspidistra elatior) are gorgeous, tough-as-nails plants that thrive in the shade. Not sun. Maybe when the homeowner first planted them, they were in the shade, and perhaps some trees have been trimmed or removed, allowing more sunshine into a once-shady bed.
Be aware of changes like this in your garden — things change over time, and sometimes those changes aren't great for your plants. You can tell these cast iron plants are getting too much sun by the brown foliage throughout the bed. If this is happening to your shade garden, you'll need to dig up plants and move them to a part of your garden that gets less sunlight, and then replant the bed with more sun-loving plants.
And when you're at the nursery looking for new plants, be sure to look at the plant tag for sunlight requirements before purchasing them. Plants that love sun and are planted in shady gardens will grow leggy, stay small and will bloom much less (if at all), and shade-loving plants that get too much sun will burn. And any plant placed in the wrong spot in your garden will be increasingly susceptible to disease and pests.
Give your plants a fighting chance! Put your plants in the right place, and monitor their health regularly.