Before our longtime mate scientist, Garth Hokanson, retired from our Guayaki family last month, he gifted us with some vital know-how on growing and maintaining yerba mate plants. Here’s his vital guide to learn more about the plant, great if you’re ready to cultivate your own Ilex Paraguariensis.
The Cultivation of Yerba Mate
By Garth G Hokanson
Yerba mate is native to a specific region of the world, principally Paraguay, Argentina, Brazil and Uruguay. This region is similar to what we call the Mediterranean climate. Coastal California with its Mediterranean climate is a perfect location to grow yerba mate plants (Ilex paraguariensis).
Mate needs shady conditions with well drained soils. It likes frequent watering. The more shade, the larger and darker green the leaves grow. Plants grown in full sun will have small, narrow dry leaves that are bleached of some of their rich green color.
Yerba mate is part of the Holly (Ilex) family. The plants are dioecious, which means that seeds may produce male plants or female plants. Each plant will have only one sex. So if you eventually would like to harvest seeds from your own plants, you need a number of plants to hopefully get at least one male and one female. Flowers are tiny white star shapes. Not very showy as they occur on the stems, under the leaves, not at the tips or a flowering stalk. Berries start off green, turn a mustard color and then red and eventually with age to a dark purple red. At any of the red stages, harvest the seeds and dry them for several weeks. The fruit pulp which protects the seeds can be removed from the seeds to speed up germination, or you can just plant the entire dried berry.
Mate can be grown from seed or propagated by cuttings. Seed takes nearly 12 months to germinate. Seeds are about the size of grape seeds and should be planted twice their diameter deep, in a very fertile planting mix. Do not start them in an inert mix, like perlite or vermiculite. Since the plants are so small when they germinate, one must leave them several months in the seed flat until they get the second set of leaves before transplanting them to individual pots. The seed has a short life. Six months is about the longest you can get good germination from yerba mate seed.
Seedlings are very fragile for the first 2-3 years. They are best grown in a cold frame, hot bed or greenhouse for the first year. The fragile plants are susceptible to snails, slugs and pill bugs, which can quickly eat the tops of the seedlings. Once the apex is gone, the plant will die. So take measures to guard against these pests. Growth of a seedling is very slow. Only about an inch a year for the first 2 to 3 years. When plants are 5 to 7 years old, you can expect between 2 to 4 feet of growth a year.
Propagation by cuttings is another way to start yerba mate. Half ripe cuttings about 4 inches long will root in perlite in about 6-10 months. Unlike the seedlings, cuttings are best in an inert media. As soon as the cuttings produce roots, they can be transplanted to a small pot with soil. Cuttings will give you a more robust plant but seedlings tend to have a vigor that outgrows the cuttings the first years.
Yerba Mate can withstand temperatures down to 15 degrees. So essentially most of coastal California up to Sonoma County are perfect locations. In the spring, summer and fall, the plants are a dark green with shiny leaves. At the first outbreak of cold weather the stems will start turning red and new growth will turn a purple to dark red color. This is simply the winter color and is normal. Extended freezes may cause plants to lose leaves, but they will grow back when warmer weather comes again. Plants do not need to be covered, if planted in the ground during bouts of cold weather. But it is critical that they stay watered, as a frozen root ball will remain at 32 degrees when air temperatures drop to the 20s. If you are growing mate in containers, then it is advised that you move the containers close to the house, under a roof eve or patio to help protect from extended cold weather.
Yerba mate comes from rainforests where dead tree trunks and leaves are continuously decomposing creating humic acid and a rich acidic soil. So a regular fertilizing plan is needed if you want to see rapid growth of your plants. Foliar fertilizer sprays or granular fertilizers will do fine. Choose fertilizers that are balanced, where the first number (Nitrogen) is approximately twice the second two numbers (Phosphorus & Potassium). Combinations like 18-6-5 or 20-10-10, etc. are examples of combinations to look for. The key is to always keep the first number Nitrogen) high, which is responsible for stem and leaf growth. Turf fertilizer is too strong. Bulb food 0-10-10 or similar low Nitrogen combinations will cause the plant to stop elongating and stop producing leaves and to begin producing seed, which is not what you want for the first 5 years.
When your plant grows large enough to harvest-about 4-5 feet, prune the plant back as you would a small fruit tree, leaving a strong limb base for future growth. Leaves and small stems can be separated from the thicker branches. Discard the thick branches and rinse the leaves and stems with cool water and allow them to dry. For best results, once leaves are dry, you can put the leaves on a cookie sheet and put them into a 400 degree oven for 2-3 minutes. This high heat (Sapecada) deactivates the leaf enzymes and keeps the leaves from fermenting. Then drop the temperature to 100 degrees for 2-3 hours. Or, after the Sapeco of 400 degrees, just allow the leaves to air dry for a couple weeks, where there is no direct sun. Placing a paper towel over top of the leaves will prevent dust from settling on the drying leaves.
Once dry, you can crumble your leaves to fill a gourd, or French press or make your own tea bags and enjoy your very own home-grown yerba mate.