Planting sunflowers in containers. I did this because of sunflower allelopathy: they can retard the growth of nearby plants. I learned later that sunflowers don't grow to normal height in containers, and these weren't a tall variety to begin with.

(Auto-correct wanted to change allelopathy into telepathy.)

Planting red morning glory seeds for a change of color. They didn't grow well. Back to the blue this year.

Using manure as mulch - my tomatoes showed all the commonly described symptoms of aminopralid poisoning and barely produced anything. I'd never heard of it until I started trying to diagnose my plants.

No manure this year!

^^ Was it aged? Aged manure is fantastic soil amendment; have never used it as mulch, though.

Yes, it was aged/composted; the problem wasn't that it was "hot" - just the herbicide, which can take years to break down from what I've read.

I'm sure that herbicide-free manure would work great and I'd use it if I could get it.

buying things on clearance, without thinking it thru. Bought these red mums cheap, I went there looking for more clearance mums but RED????? I had never seen that color before,

another mistake I made, which was pointed out here, clear sign of a newbie is that I alternated rose and mums instead of mass planting. I have been contemplating changing things around, but in some ways I really liked having drift roses in bloom from Spring to fall and then when fall came I was blown away by the clearance mums from the year before, I kept cutting the roses back to let the mums do their thing...I loved the fragrance of the Peach drifts and constant flowers however I didn't find the shape and leafs all that nice. So here I am excited for Spring and trying to figure out what to do. Playing with garden puzzle. Here is my new bed plan

you can see my alternating roses and mums in the old bed. It may be a newbie mistake, but I still kind of like it. this is "summer" on garden puzzle. I had to use things that were close to what I have, I have Bo-bo's and rose of Sharon "trees" both lavender but one is a double and one is lavender chiffon, the new plants I'm thinking peonies, stellas, PJM, drifts, and thinking of throwing in more mums

Spring

That aminopyralid class of herbicides are terrifying! After being used on grass-family crops such as hay, grains, and straw, they keep their herbicidal action through the digestive system of animals, and then through the composting process of the manure. They make your soil fit only for growing grass-family plants -- I guess this year you can grow corn where you put that manure last year. I hope you didn't put it everywhere!

The good thing is from what I read, the only thing that helps aminopyralid herbicides break down is sunlight, so if you keep the manure on the surface as a mulch, hopefully they will break down.

@bernbecca, I've been wanting red mums and couldn't find them where I live! Too bad I live on a different continent from you or I'd offer a swap.

My mistakes are more that I had a few too many things on the go, which is a constant for me. But last year, it was a bit much, even for me, and I felt like people were gravitating to my multi-tasking, and adding even more on top of that. So, I've slowly been paring down things and obligations and really glad to now just be doing my own thing. Always working at simplifying things...