Prairie gardening tip: What to plant in place of a tree infected with fire blight.

A few weeks ago, I was sent a question about fire blight – a gardener had a seriously infected hawthorn tree cut down in her yard and the arborist left the chips on the ground. She wanted to know if she should remove the chips or keep them; her second query was what types of trees she should plant in the hawthorn’s place. Fire blight is caused by a bacterium called Erwinia amylovora. It is spread by insects, birds, wind, and water, so it is likely to have traveled from another infected plant nearby.

My recommendation was to remove the chips and dispose of them at a landfill. As for the trees, fire blight affects members of the rose family, so I advised her to avoid those, or at the very least, look for cultivars within those genera that are fire blight resistant. Trees that are susceptible to fire blight include:




Mountain ash


Saskatoons (serviceberries)


There are a few shrubs to avoid as well, including roses, spirea, and cotoneaster. Raspberries can also get fire blight but it is a different strain than the other plants mentioned can contract. By knowing which plants to avoid, better choices can be made about the new selection.

Janet Melrose and I have written more about fire blight – including how to ID and attempt to control and prevent it – in our book The Prairie Gardener’s Go-To for Pests and Diseases.

Do you grow any members of the rose family? Have you ever had an issue with fire blight?

Botany word of the week.

Aggregate fruit (as well as some bonus chatter about accessory and multiple fruits, pseudocarps, drupes, achenes, carpels, and…um…monkey bread?)

Occasionally (or possibly frequently, given the weird world we live in), things turn out to be different than advertised. Sort of like that purse I ordered off of the Internet. But I digress….

Case in point: raspberries and strawberries.  Are they actually berries?  You already know where I’m going with this!

What does it mean to be a berry?  Quite a few things, really, but one of them is that the fruit must develop from a flower possessing one ovary.  Strawberries and raspberries don’t fit the bill.  If you take a look at the fruit of a raspberry, you’ll notice that it is made up of a bunch of little nubs. You could pull each one apart, kind of like a loaf of monkey bread.  (Mmmm…how can you tell I haven’t eaten breakfast yet?).  Each one of these is called a drupe (drupelets), and they are produced from the multiple ovaries of a flower.  Each drupe contains a seed.  In the case of a strawberry, those little seed-like things on the outside are not actually seeds, although they do contain seeds. Those small bumps are called achenes.  Because these fruitlets were all joined together, they are called aggregrate fruits.  (Just to be confusing, not all multiple fruits – those with more than one ovary per flower – are aggregate.  Some don’t join together to form a single entity).


And, to add to the fun, strawberries are categorized as an accessory fruit (aka pseudocarp) in addition to an aggregate fruit. Some of that yummy fleshy stuff we eat is made up of tissue that originates near the carpel (modified leaves that surround the ovules) of the flower.

Okay, now that we’ve got that out of the way…I’m off to enjoy an aggregate fruit smoothie!  (Doesn’t have quite the same ring to it, does it?).  Do you grow raspberries and/or strawberries in your garden?  What ways do you use them in cooking and baking?  

Geggel, Laura, “Why are Bananas Berries, but Strawberries Aren’t?”, LiveScience, January 12, 2017,
UCMP Berkeley , “Anthophyta: More on Morphology,” accessed March 3, 2020,  (This is a really good resource if you need a refresher on how fruits are formed).