In mid November while attending the Partners in Community Forestry Conference in Sacramento, I picked up a few acorns from various types of oaks around the area. Part of the conference included a tour of the Shields Oak Grove at the UC Davis Arboretum – the home of more than 80 species of oaks from around the world. I saw oaks I never even knew existed, including a unique oak from Mexico with very stiff and large leaves. Of course, I had to pick up a few acorns to see if I could grow any of them. The only viable acorns I could get my hands on were that of the bur oak (Quercus macrocarpa). I had never seen an acorn like this before. It was covered by a large, protective cap with rough furry edges, as seen in the picture below.
In downtown Sacramento, I picked up a few cork oak acorns (Quercus suber). These trees have incredibly interesting bark. It’s called cork oak because the bark is the source of commercial cork for wine bottles, etc. (like I needed another reason to love a tree). I came upon a whole slew of these acorns on my way out of the hotel and was very excited about the possibility of growing one of these beautiful trees.
I was excited to stick these acorns in the ground to see what would happen. Fortunately, I was surrounded by hundreds of arborists (I’m still in training). One of them, my co-worker in fact, was able to explain what to do as easily as if she was telling me how to start a car. It’s so easy, that any of us can do it. Hence the title of this post: “An oak tree?
Here are the steps:
1) Find viable acorns. This means they aren’t dried out or damaged by insects or animals. If you wait too long after collecting the acorns, they will lose it’s ability to germinate.
2) Float test: remove the caps off the acorns and drop them into a glass of water. If the acorn sinks, it will grow; if it floats, it won’t.
3) Get some vermiculite, wet it enough so that it’s moist without being soggy. Put the vermiculite in a bag with the acorns.
4) Place the bag in the refrigerator for approximately one month for germination.
5) Once roots are growing out of the acorn, remove and place in a pot large enough for the taproot to grow.
6) Repot in larger pots as it grows, or plant in the ground.
And ta-da! You should have a new oak tree seedling. Remember, that not all seeds will grow, so it’s best to prepare several acorns if you’re hoping to get one tree.
Considering sudden oak death (SOD), the gold spotted oak borer beetle, etc., it’s not a bad idea to do what we can to try to grow more oak trees. Whether you plant them in your backyard or in a nature preserve, growing more can help oak populations out.
Here’s my experience with this process so far:
Removing the cap from the bur oak was NOT easy, but it was so big that I figured it would interfere with the float test. Unfortunately, the acorn didn’t exactly sink to the bottom, nor did it immediately float to the top. I have a feeling it’s not going to grow, but I’m trying it anyway.
After only about 2 weeks, one of my cork oak acorns has already sprouted. Yippee! You are seeing potting soil on these acorns. I didn’t have any vermiculite or sawdust, so soil was the only substrate I had available at the time. I wasn’t sure how well it would work, but so far so good. I’ll be happy if I get one seedling out of this experiment. Just think, if I start growing a cork oak now, it may be ready by the time I decide to take up winemaking! (Don’t worry, harvesting bark for corks is sustainable and will not kill the tree.)
On the fourth day of each month, garden bloggers everywhere are coming together to post about what you can grow. Posts will be about anything from growing hops for your home brew to growing your own wedding bouquet. To see others, check out the You Can Grow That! Facebook Page. More on this can be found at C.L. Fornari’s blog.