I have two japanese silver grass plants in containers on my apartment patio. I would like to keep them for next year. If I put them in the garage over the winter ( Buffalo, NY) will they live. Should I cut them down in the fall or sprint?
Perennials in containers can usually survive outdoors approximately 2 Hardiness Zones warmer than they will tolerate in the ground, so you likely will need to provide some protection for your grass plants. An unheated garage may work quite well. Leave the grasses outdoors through fall, until temperatures drop into the low teens or so. This will force them to go dormant. After the tops have been frozen back, you might as well cut back the foliage to make them easier to handle.
They may need watering a few times through the winter to prevent the soil from drying excessively. Also watch for signs of growth in early spring. You may need to move the containers back outdoors to slow the growth if they start "stretching" in the garage from low light and warm temperatures.