First Signs of Trees Breaking Winter Dormancy

Deciduous trees in Albany, CA are beginning to show signs of breaking winter dormancy.

---

We don't usually write about anything other than insects on here (it's an insect blog after all), but since botany and entomology go pretty much hand in hand, it doesn't hurt to talk about plants once in a while. Because most insects are herbivores, the seasonality of their life cycles correlates strongly with the seasonality of plants. Thus, we always make sure to keep a good eye out for when the trees begin to break winter dormancy and plants begin to grow again so we know when to expect certain insects. Here in Albany, CA (and much of the state), the winters are extremely short and relatively warm, and thus trees begin to grow as early as February unlike most other places in the country where you usually have to wait until April or May.

Plum trees are usually the first of the fruit trees around here to bud, opening hundreds of blossoms in the course of a week or two followed by leaf growth. Just a week, our cherry plum tree (Prunus cerasifera) was only just starting to get flower and leaf buds all over its branches, and now it is covered in blossoms and leaf shoots. Once the blossoms fade, we can expect it to be green in a few weeks for our cecropias to feed on.

Some other trees in our backyard that are breaking dormancy are our rose (Rosa sp.) and lilac (Syringa sp.), which had no traces of green two weeks ago. Rose grows quickly and will probably be nice and bushy in a couple weeks. Our lilac tree is quite small and hasn't done very well in past years (it hardly bloomed last year), but this year it looks like it has a lot of buds that are budding and will probably open in the coming weeks.

Our lemon tree (Citrus limon) has been heavily pruned this year despite that citrus trees shouldn't be pruned much, simply because it is a very old tree and was becoming unhealthy so we wanted to reinvigorate it. Citrus trees are tropical and subtropical plants so they grow in response to rainfall changes and not temperature changes, but since this time of year also happens to be the rainy season, you can see the tree is beginning to grow and has several new shoots. Lemon tree shoots typically have a high concentration of anthocyanin which gives them a purple color while most other citrus are just green. 

We also have two apple trees (Malus sp.) in our back yard, one of which is quite large and vigorous in the summer while the other is sort of scraggly and only moderately vigorous. Right now both appear dormant with no signs of green, though it is possible that the buds are enlarging but we're not quite sure. Historically, they should start blossoming in March and have leaves by April, so it's still a bit early. However, it has been an especially cold and overcast February this year which may cause they to blossom a few weeks later than usual, but we'll see. Hopefully they will be ready in time for our cecropias which we anticipate to hatch some time in late March. 

- Alan