In April 2025, we went to the Boysenberry Festival at Knott’s Berry Farm. The festival has a wide variety of food and drink with a boysenberry flavor. It is a lot of fun to attend and I highly recommend it. While walking around we noticed that there were a couple of booths that sold actual boysenberry plants to take home. Being as Knott’s is the reason that people even know what a boysenberry is and being able to purchase one at the park, I decided to go ahead and try my luck with one. The plants also came with instructions written by Walter Knott himself, which I felt was something of a bonus. If anyone knew how to grow these plants, it was him. Well, that and Rudolph Boysen.

Let’s talk about some of the details of our little garden.

Geological Conditions

The area chosen for the garden was the site of a makeshift greenhouse which was torn down just before we purchased the house. A large amount of potting soil with a heavy amount of perlite was left in the space to a depth of a few inches. Below this was some artificial fill from construction and the original bedrock. Here, the bedrock is composed of 855ka Pleistocene sandstones and conglomerates, known as Quaternary Very Old Paralic Deposits, Unit 9 or Qvop9 for short. These were shallow marine terrace deposits with a heavy amount of clay, similar to what is currently forming at the coast today. In terms of our backyard, digging usually requires a pick and shovel as well as removing large rocks.

Original Planting

The first time I planted the boysenberry, I dug a hole a little larger in the upper soil than the plant and created a smaller ring around it at ground level. After a while, I reread the instructions and expanded the ring to about twice its original size. The ring acts as a levee for watering and a defined area to keep clear of other plants. I also added two metal poles on either side of the plant with wire connecting them for a trellis. I watered the plant often and it gradually took hold. Initially, the main stems that existed when I purchased the plant started to wither, which was unfortunate, though a new stem started to form and grew rather quickly. I checked it out pretty much daily and saw quite a difference each day. As the leaves got larger, I also started to notice that some were being eaten.

The bug eating the leaves looked like a tiny grasshopper. At first, I was able to “scare” it away but more came each day. Our backyard also has lizards, which I happily found out eat those bugs. Still, it got worse. One morning I came out to check and an entire leaf was covered with these bugs. I did a bit of research and found that neem oil, the same thing we used for other bugs on our citrus, worked to kill these things. I sprayed quite a bit and it took care of them.

This spraying seemed to also stop the growth of the plant. Despite seeing rapid changes daily up to this point, all growth stopped and the leaves started to turn darker colors. Some of the leaves even dried up.

I kept watering it and monitoring it as much as I could but had given up some hope it would return. It turns out, it was just dormant, and would indeed return.

New Plantings and Construction

In March 2026, we returned to the Boysenberry Festival and purchased two additional plants. These were in much better shape than the ones last year. I also got additional instructions on caring for them, given the conditions in the backyard. Learning the lessons from last year, I dug a large area around where the plants would be placed. The hole ended up being about 4 feet long and 2-3 feet deep. The intent was to break up the soil around the site so the plants would have an easier time. It also offered an opportunity for soil treatments at a deeper location.

I spaced the plants about 4.5-5 feet apart to give as much room for growth. New posts were also placed to expand the existing trellis system. A pathway was built adjacent to the plants and a survey monument was also placed for future surveys of the yard. A wood chip mulch was added around the plants and the path was formalized soon after with gravel and pavers. A rock garden was also added next to the path and will be expanded as materials permit.

Plant Progress

The new plants took hold pretty quick and even the original one got going again. Things were looking pretty good with the furthest plant getting the tallest growth. Watering was via a bucket usually twice a day. This growth was sustained until early June when I noticed a gopher or mole burrow at the furthest plant. After just a couple of days, the plant was starting to wither. It was then I noticed the animal had eaten the bottom of the plant almost entirely and cut it off. After doing a bit of research, I found some countermeasures that seemed to work quickly. I also tried to propagate the existing cut-off stem by placing it within the existing plant area. It did start to take hold, though had to be shortened quite a bit. The original plant also started to grow again, which was a good sign. I also installed a drip watering system to facilitate more consistent watering and reduce issues while we are away, especially with the summer heat coming soon. They get watered for about a minute each morning and I am working on a way to water them again at the end of the day.

Current Status

All the plants are still growing at a decent pace. The middle one is now the tallest with both on either side seemingly adding a stem every few weeks. The furthest plant which was damaged now has increased growth with new stems. The former stem is maintaining but nothing new seems to be growing yet.

We’re looking forward to seeing some flowering and berry production once they are finally big enough to support that. The whole experience has been a lot of fun and I encourage anyone that has the ability to bring home some Knott’s Boysenberry plants to continue a Southern California tradition.