To continue my education I purchased the book below, What's Wrong with My Plant? It is well laid out using a flowchart to lead you to the possible issue.
The mandevilla below has old leaves turning yellow but still has new growth. The flowchart led me to nitrogen or magnesium deficiency. Not rocket science on that one but I realized that I fertilized it's neighbor but not this newer addition. I gave it some fertilizer. Let's see what happens.
The lantana has suspicious leaves. I'll research this today to see what ails it. Leaf miners? Hmmm.
Now for the happy places. I filled a hanging basket with cyclamen, snapdragons, and petunias. It's wonderful to have cooler weather. The previous tenant of this basket dried up in the heat.
The passion vine on the right has gone over to it's neighbor, the clematis, on the left. It is so much fun to watch both of these vines cover the pergola. I love sitting out here in the evening.
And a basket of roses to look at each day. My mother had miniature roses at the front of her house. I think of her when I look at these. I love all my plants but nothing is as pretty as a rose. Passing by and taking a sniff makes me happy.
I hope fall weather has hit your area. It's a beautiful time of year.