One inch to 6 inches per year? Huh? Why can’t they decide?

We often see this kind of information on a plant tag at the nursery, or in plant listings online, the growth rate that differs as much as one foot sometimes.

Why don’t we know how big it grows? What’s up with that?

This kind of growth rate information is common on plants that are shipped by the larger nurseries throughout states and Canada. Instead of creating a dozen different tags for each climate zone the plant can be grown in, they group the rates together on the one tag to save time and money.

I found this out when I started mailing plants, years ago through Ebay. A woman from the East Coast engaged me after purchasing some plants and was asking about the growth rates, as she wanted only true miniatures for her collection. I sent her some wee conifers and signed off for the season.

I got back in touch with her in the fall, only to learn that the wee conifers grew too fast that summer.

“But, they were slow-growing dwarfs, about 1.5 inches per year?” I queried.

“In Seattle they are. In North Carolina, they aren’t!” She said.

Previously, I had only sold at shows and markets around the greater Seattle area, so there wasn’t any need to hold on to that kind of information – unless I wanted to move to North Carolina, I guess. But with selling online I had to quickly get an understanding of the zones, throughout the country, in order to help my customers.

Over the years of doing classes and teaching I’ve also learned that this also why the word “Dwarf” irks people.

“Hey, Janit. See that pine growing over the rooftop of my house? That’s a dwarf too!”

Dwarf is only a growth rate and while your big pine tree may match the height of your house at maturity, it is still a dwarf version of one that would be well more than 100 feet tall and found in our natural forests.

The official growth rate for dwarf is 1 inch to 6 inches per year. That’s a half of a foot. That’s a lot, especially if you’re into miniature gardening.

The Jean’s Dilly Dwarf Alberta Spruce grows 1 inch to 3 inches per year. Here in cool Seattle (ignoring this past summer), that Dwarf Alberta Spruce might grow 1.5 inches per year. In a climate with a longer and hotter summer, it will grow closer 3 inches per year.

So, you can roughly gauge where you would be on a scale of 1 to 6 inches, by thinking about your climate compared to the rest of the states and Canada collectively.

Still keeping the Dwarf Alberta Spruce as an example:

- 1 inch is in the coldest region, Cold Hardy Zone 4, or -30F, Lower part of the upper States.

- 6 inches in the warmest zone, Cold Hardy Zone 6, or 0F. Lower part of middle states and up the West Coast.

Long cold winters, short, hot summers, 1 inch per year. Shorter winters and longer summers further down south would be 6 inches per year.

I hope this is of help to some. And happy planting season!