I fell in love with the cacti I saw during my recent visit to the Milwaukee Dome Gardens. (A must see for plant enthusiasts!) Cacti are very recognizable plants with waxy skin and prickly spines. They grow in a small part of Africa and Madagascar, but the largest expanse of their territory is throughout the Americas, with the highest concentration located in Arizona, Texas, and Mexico.
They come in all different shapes and sizes. The tiny blossfeldia liliputana maxes out at only 12-16 mm across. That’s as small as a penny! The largest is the Mexican giant cardon cactus which stretches over the top of its cousin, the Texas saguaro, at 64 feet! They can live to be quite old as well. The oldest living cactus is the cardon at 300 years old!
The Sonoran Desert is an icon of the American South with a ‘forest’ of tall armed saguaro (pronounced saw-wah-roh) cacti growing within Organ Pipe National Monument in Arizona*. The majority of a cactus’ roots grow only inches below the soil to collect as much water as possible in the arid desert. Their trunks are also pleated to collect and shunt water directly to their roots. During an extended drought, a cactus will actually shrink while it lives off stored water in its cells. As a result, a cactus can expand and jump significantly in weight after a single rain storm. A full grown saguaro can weigh as much as a ton! Don’t let that fall on you! Ouch!
Living in extreme desert conditions can really affect the growth rate of the saguaro. It can take nearly 10 years for a baby seedling to grow a single inch. By the time they are six feet tall and blooming size, that cactus is as old as grandpa at 75. At 100 years old, it has reached a height of 15 feet and is producing its first arm. By 200 years old it has grown to the full height of 45 feet.
For a fun project, try growing cactus from seed! Because they will be growing in your house vs. a desert, they’ll grow a little faster for you. I purchased and grew a package of seeds 13 years ago. The one I gave to my sister is now an adorable 3 inches tall. To grow from seed, save a plastic blueberry container from the grocery store. The holes make for good drainage and the lid acts like a little green house. Use a mix of 1 pt. potting soil and 1 pt. coarse sand. Get the soil wet and sprinkle the seeds on top of the soil. Do not bury. The seeds need light to sprout. Place in a bright location or under grow lights. Keep moist by misting until sprouted. This can take 3-4 weeks. When they are about the size of a pea, quit misting them and only water once a week. Spines will appear; that’s a sign to pop open the container lid. Once they are an inch tall, use tweezers to repot into tiny 2 inch pots. Only pot up when the cactus is nearly at the edge of the pot’s rim. Use rolled up newspaper like a tourniquet to lift larger plants from their pots to avoid stabbings! Water cactus over two inches tall only once a month and not at all in December. ☺
*More info at nps.gov Organ Pipe Cactus National Monument.