Dr. Wife and I have a treaty which states that I can plant whatever I want so long as I don't take up any more yard space than I already have. So back in March 2011 when I came home from Plants for All Seasons with two avocado trees, I wasn't sure where I would put them at first. Since I didn't have any more yard space, I decided to plant my new avocado trees in big 30-gallon pots up against our big pine trees. I would have liked to plant them in the ground here, but the big roots of the pines made it very difficult to dig, and the drainage in that area is relatively poor. I had tried growing Mexicola Grande, Lila, and Fuerte in that general area, and they all died from poor drainage, freezes, sunburn, or a combination of the three. Planting in big pots would ensure good drainage, the pines would help shade the avocados, and I could stay on good terms with Dr. Wife.
On field trips to John Panzarella's and at Devine Avocados, I had seen avocado and citrus trees that had escaped their pots, and taken root in the surrounding native soil. Hoping my trees might do the same, I sneakily cut some holes in the bottoms of the pots when I planted the trees, and buried the pots an inch or two into the ground. Well, It's been almost two years since I planted those trees (Brazos Belle and Poncho), and in that time they've grown like crazy. They really took off when I hooked them up to the automatic drip system in my greenhouse, and they started to get smaller applications of water every day instead of deep waterings once or twice a week. I knew that at this rate they would soon outgrow their 30-gallon pots, and that if I wanted their roots to escape to the freedom of the native soil, I would have to help break them out.
First, Boy #1 and I took a little side trip to a place I know with lots of good sandy topsoil, and dug and dug until we had 12 5-gallon buckets full of dirt. We hauled it all home and lugged it to the back yard. I pulled back all the mulch and pine needles from around the pots, and did my best to rough up the soil around them. Then using a sharp utility knife, I cut square holes approximately 3-inches by 3-inches all the way around the bottom of the pots. Healthy bright-white roots were clearly visible encircling the pots, and I did my best not to slice them as I cut the plastic. I also tried to loosen up the soil and gently tease out the roots out of the holes using a garden hose and my fingers.
Once the holes were cut, Boy #1 and I began banking the sandy topsoil around the pots; six buckets of soil for each tree. As we worked, we mixed the topsoil with MicroLife 6-2-4, composted kitchen scraps, and a little humate to help encourage the avocado roots to escape. The 30 gallons of topsoil we placed around each tree resulted in a nice donut-shaped raised bed around each pot, approximately 6-inches deep and a foot or so wide. Finally, we covered the topsoil with several inches of leaves and pine needles, and watered it down. Hopefully, as fertilizer and water from the drip system drain out of the new holes and into the banked topsoil, the roots will follow and eventually take hold in the native soil.
Boy #1 helping me dig up 12 5-gallon buckets of sandy topsoil.
30-gallon pot set a couple inches into the ground.
My avocados made it through the brutal summer and are blooming. Last year the Brazos Belle set 16 fruits, but none of them made it to maturity. I'm hoping to get at least one this year. Honestly, I'm just happy I was able to keep them alive. Interestingly, the Brazos Belle is covered in blooms but isn't putting out much new growth, while the Poncho is pushing out lots of new growth with very few blooms. I've noticed similar behavior in citrus; oranges seem to like to put out blooms followed by new leaves, but the satsumas are just the opposite.
Avocado flowers are dichogamous (like pecans), which means that the male and female flowers on a tree mature at different times. This is a strategy that has evolved in avocados, pecans, and other plants to prevent self-fertilization and promote genetic diversity. In protogynous (female first) or Type A flowers, the pistils are receptive to pollination for a period in the morning, the flower closes, and then reopens to shed pollen in the afternoon in response to warmer temperatures. In protandrous (male first) or Type B flowers, pollen is shed in the morning, and the flowers reopen as female in the afternoon.
According to the University of California at Riverside, when daily temperature average (including night and day temperatures) is less than 70º F the daily switch between male and female becomes irregular, and one tree can have both male and female flowers at the same time. Houston’s average daily temperatures are usually around 70º F or less in early spring when the avocados are blooming, so under normal circumstances it isn’t necessary to plant both Type A and Type B trees. This is good considering that I have found very few nursery owners who were even aware that there are different types of avocados, and no one who could tell me the types of the different Mexican avocado varieties.
Speaking of nurseries, the same genetic clones are marketed under different names, and it can get confusing trying to keep them straight. I've even seen the same variety sold under two different names at the same nursery! Here's a key to the different varietal synonyms:
Brazos Bell is a genetic clone of Wilma. It can be easily recognized because it's branches are 'wimpy'.
Lila is a genetic clone of Opal (aka Holland, or Opal Holland). It is considered to be the second most cold hardy Mexican avocado.
Poncho is the same as Pancho. As far as anyone can tell, it's just different spellings of the same name.
Fantastic is Treesearch Farm's trade name for Pryor. This variety is considered to be the most cold hardy of all the Mexican avocados.
Even though these are genetic clones, not all avocados are propagated equally. If you buy Brazos Belle or Lila, you won't know what rootstock was used. However, if you buy Wilma or Opal, you can be sure that it is grafted on cold hardy Mexican rootstock. The absolute best place to buy avocado trees Bill Schneider's place in Devine, Texas. It's a long drive, but worth it. I still haven't found a fruiting avocado north of I-10. If you know of one, send me a picture.
I recently got shipped out to Bigfoot, Texas for work, approximately 35 miles southwest of San Antonio. While I was there, I took a little side trip to visit Bill Schneider, owner of Devine Avocados in Devine, Texas. Have you seen the cold-hardy Wilma™, Opal®, and Pryor® avocado trees at local nurseries and fruit tree sales? We have Mr. Schneider to thank for these varieties.
I asked him how he got started with avocados in the first place, and the the basic story goes like this: Bill and his father took a trip down to tour the Rio Grande valley. While down there, they bought 40+ young Mexican avocado trees from a professor at the Texas A&M research center. By the time they got back they had sold all but one, which they planted. The tree grew and produced wonderful avocados.
Later, when driving through Pearsall, Texas, he noticed a beautiful large avocado tree in a backyard. He stopped and talked to the old woman who owned the tree, and asked her if he could take some cuttings to propagate. She said yes, and Bill said that in return he would name the variety after her. Her name was Wilma Lechler. In a similar fashion, a visit to a backyard tree in Uvalde, Texas gave us the Opal® avocado.
I also learned that Wilma™ is not the same as the variety advertised as Brazos Belle, as I had previously read. They are the same genetic clone (Lechler), but the Wilma™ is grafted on a particular rootstock in a specific way as to give the best chance of success in potentially frost prone areas. As I understand it (and feel free to correct me if I'm wrong) the Brazos Belle is genetically identical to Wilma™, but it can be grafted on any rootstock.
In addition to being an avocado expert, Bill is also growing Capulin cherries, mulberries, jujubes, pears, pineapple guavas, and a variety of citrus. I had a great visit, and can't thank Mr. Schneider enough for his time and willingness to share stories and information. I learned a lot, and hope to be able to return soon.
® Registered Trademark of Devine Avocados ™ Trademark of Devine Avocados
The Mother Trees.
These trees have suffered significant freeze damage the past two years, but they're coming back.
I am very excited at the prospect of actually getting to pick and eat an avocado. As I discussed in a previous post, this year I bought a Brazos Belle (Not the same as Wilma) and a Poncho avocado from Plants for All Seasons. They both flowered, and the Brazos Belle set somewhere around 25 fruits. Avocados are self thinning, and after a few months, I'm down to four small avocados approximately 3 inches long. I was going to pick them off, thus allowing the tree to put its energy into growth rather than fruiting, but I didn't. The allure of picking and eating an avocado from my own tree is just too strong.
The Poncho didn't set any fruit, but it is growing very very well. It is covered in several new flushes of growth. I imagine the Brazos Belle would be also, if I had removed the immature fruits. Both trees seem quite happy in their 30-gallon pots under the pine trees, where they get afternoon shade and some protection from the wind. Dr. Randall once said that you should plant an avocado tree in the shade of a tree you don't like, and when the avocado gets big and established, cut down the other tree. Nothing would make me happier than to take out those big pines.
I was looking at my Mexicola Grande the other day and realized that it was smaller than when I planted it three years ago. The freezes of the past two years have really been tough on it, and it just looked terrible. This variety just can't make it in my yard, it's not cold hardy enough. I figured it was time to admit defeat, so I dug it up and put it in a pot. I planted a Capulin cherry in it's place, which will hopefully fare much better.
My goal is to have the first fruiting avocado tree in Houston north of I-10. If you know of someone who already has one, please send me an email, I'd love to see it (and take a cutting). Two years ago I planted Mexicola Grande and Fuerte avocado trees. The Fuerte was killed by the '09-'10 freeze, and the Mexicola took significant damage. I replaced the Fuerte with a Lila avocado. The bad freezes this year only slightly damaged the Lila, but the Mexicola was hit pretty hard again.
I was at Plants for All Seasons this weekend, and their avocados looked so good, I couldn't help myself. Plus, they were about $20 cheaper than I had seen them at other places. I picked up a Brazos Belle and a Poncho, both reputed to be especially cold hardy varieties. They were both in bloom, and really tall and skinny, so my guess is that they've been in a warm greenhouse all year. The environment in my backyard is a little more demanding, so I hope they can cope with our Houston winds and weather.
Several nurseries such as RCW now advertise cold hardy avocados, many varieties of which were developed by Devine Avocados near San Antonio, Texas. What they don't tell you is that often, these cold hardy cultivars are grafted onto Lula rootstock, a vigorous but frost-sensitive variety. So if you plant the cold hardy tree, but the rootstock is exposed, freezes can still kill it. To get around this, avocados need to be planted deep in order to bury the graft, and thus protect it from hard freezes.
My agreement with Dr. Wife is that I can plant whatever I want, as long as I don't take up any more real estate in the yard. Since I don't have any more room, I decided to plant the new avocados in 30-gallon pots under my big pine trees. The pots will ensure good drainage, and the pine trees will protect the young trees from sunburn.
I hate freezing weather. When I started planting fruit trees a few years ago, all the weather data for the past 10 years suggested that I wouldn't see temperatures below 27 degrees. Last year I got hit hard with 17 degrees. I thought it was a freak occurrence, and hoped for a mild winter the following year.
BAM! Hit again, this time with a low of 19 degrees, and almost 3.5 days with temperatures near or below freezing. I did my best to protect everything, but there was only so much I could do against rolling blackouts and strong winds. Unfortunately, it's not over yet. Another hard freeze is predicted for tonight and tomorrow. Hopefully this will be the last one of the year. I've tried to summarize the levels of cold protection and their relative effectiveness below. I'll have to wait until early spring to see the full extent of the damage.