Acres of acorns and stubborn gardenia

QIs there any significance to this year’s bumper crop of acorns — relationship to past weather conditions, or future weather predictions? I guess the squirrels are happy.

— Vicki, Bay Area

AFor centuries, humans have been trying to find connections to why oak trees produce mass quantities of acorns one year and not the next. Theories include harbingers of a hard winter ahead, the arrival of a drought or the wrath of the gods.

The truth is, scientists aren’t exactly sure, although they are certain acorn production is not a predictor of the future. It’s mostly all about botany.

Oak trees produce what are known as mast years — what farmers might call a bumper crop — every two to five years. It’s a natural thing, similar to how some fruit trees bear heavily one year and not the next. After a mast year, acorn production the following year is much lower, probably because the tree expended a lot of energy putting out all those acorns and is taking it easy the next season.

There are theories that the weather, rainfall, humidity and other factors might trigger a mast year, but we aren’t sure which ones carry weight or how much weight they might have.

Oak trees, like all plants, are hardwired for survival. That’s pretty much all they purposely do — produce seed to ensure future generations. Putting out lots of acorns helps assure that.

Some people theorize that oak trees somehow know there are a lot of squirrels, birds and other animals waiting to devour the acorns and stash them away for the winter. The oaks produce a lot so that animals can have their fill, while leaving plenty of acorns behind to germinate.

While that’s the end result, it’s not the cause, and the oak tree has no special knowledge of animal populations.

This gives more credence to the theory that prime oak tree weather conditions the year before can trigger a mast the following year, although that isn’t always the case. Sometimes oaks produce masts following a really bad year.

And then there’s the marginally unsettling fact that oak trees can communicate with each other. Not by voice, text or Tweet, but through chemicals. Apparently, oaks emit chemicals that tell other oak trees it’s game on, start producing lots of acorns. Thus instead of one tree producing an abundance of acorns, all the trees in an area produce them.

Q

I planted a small blooming gardenia that was given to me as a gift three years ago and it hasn’t bloomed since. Buds never form but it looks green and healthy, and I fertilize it with an organic fertilizer for acid-loving plants.

It gets full sun most of

the day. Often the growing tips of the plants look like they might differentiate into buds, but then they don’t.

Also, are coffee grounds good fertilizer for plants and good to add to the compost pile?

— Nancy Lucid, Bay Area

AGardenias can be tricky. The three main reasons they don’t bloom are temperature, lack of nutrients and improper blooming.

Gardenias like mild temperatures — not too cold, not too hot. In the spring, in order to bloom, they like it to be 65 to 70 during the day, and no colder than 60 degrees at night.

Depending on where you live, it might just be the wrong conditions for it to bloom.

You’re right that gardenias like an acidic soil. Ideally, your soil ph should be between 5.0 and 6.0. As most of our soils are clay, you might want to consider planting it in a pot, where you have better control over the acidity. Just adding an acid fertilizer won’t change the ph in the ground.

Fertilize your gardenia lightly in the spring, and again in about six weeks, using an acidic fertilizer.

If you prune your gardenia, prune in the summer, after the plant has finished bloomed — or in your case, after it should have bloomed. Gardenias form buds in late summer and early autumn that will then break in the spring. If you wait too late to prune, you could be cutting off potential flowers.

Also, while gardenias can handle full sun, you might need to protect them from the baking midday sun. An exposure where they get the full morning sun and some midday light could do the trick.

As for the coffee grounds, they are a great fertilizer for most plants and also can be used in your compost bin. Despite their coloration, they are considered a “green” element in the composting recipe as they are full of nitrogen. You’ll need to balance them with a “brown” ingredient.