Mexican oregano isn't a really oregano at all. Instead it is a hardy member of the verbena family that resembles both the taste and appearance of real oregano. Unlike traditional oregano, Mexican oregano is a heat-tolerant perennial. It can be successfully grown outdoors in areas with mild winters and hot summers, or grown indoors in areas with cold winters. Properly caring for your Mexican oregano in winter ensures it will continue to thrive for years. Growing and cooking with Mexican oregano is nearly the same as traditional oregano.
Grow Mexican oregano in an 8-inch to 10-inch pot filled with well-draining potting soil. Only plant the oregano in a garden bed if your winters rarely have temperatures below 40 degrees F.
Bring the pot indoors prior to the first frost in fall. Place it in a sunny, south-facing window so it receives at least six hours of sunlight a day.
Mulch around outdoor oregano with a 2-inch to 3-inch layer of straw or wood mulch. This preserves the soil temperature throughout winter.
Water the plants when the top 1 inch of soil feels dry when you stick your finger into it. Water potted plants until the excess moisture drains from the bottom drainage holes in the pot. Water outdoor plants in winter as necessary to keep the soil moist.
Harvest Mexican oregano leaves as they are needed in the kitchen all throughout winter. Snip off leaves as long as the plant is at least 6 inches high and always leave at least one set of leaves on each stem.
Cut back the plant in late winter to encourage new growth in spring. Cut back every branch so only one or two leaf sets remain on each branch then water thoroughly after trimming.
Fertilize potted Mexican oregano once a month throughout while it is actively growing in winter with a liquid houseplant feed. Fertilize bedded plants in spring with a balanced fertilizer. Follow package instructions for fertilizer amounts.