The Garden's Last Hurrah by Nancy Shepard

 

Supertunia Bordeaux - always outstanding in my yard
Photo: Nancy Shepard

I am determined to squeeze out the last possible beauty from my perennials, annuals and vegetables this season. I’ve watched all the big attractions bloom and retreat like peonies, bleeding heart, Chinese poppies, and Delphiniums.  My green beans and tomatoes are barely producing so I know those are ready to say goodbye. With only some hibiscus, roses, bee balm and hostas, I’m concentrating on just maintaining good foliage, raking and applying mulch to the beds. All of my Plant Select specimens still have noble endurance especially my Sunset hyssop (Agastache rupestris.)  My annuals, despite the heat, always seem to persevere with trimming, watering and fertilizing.

Annuals

My annual flowers benefited earlier in the season by alternating high nitrogen (24-8-16) with high phosphorus (15-30-15) fertilizers. The higher nitrogen is useful when they are rapidly growing in the spring, but mid-summer into fall the application of high phosphorus keeps them blooming longer. But I've always diluted these fertilizers way down. Excess phosphorus can be detrimental to the environment  because of runoff and its threat to water quality. See the link below for more about using phosphorus. Also, significant pruning of leggy petunias other annuals like geraniums really helped them keep going. I find that snipping off a third of their growth produces more re-blooming than deadheading does. My zinnias have withstood the heat and been constant bloomers, with little to no deadheading.  Since they are in pots and with the heat this summer, they have required more frequent watering.  

Zinnias
Photo: Vicky Spelman

Mezoo (Dorotheanthus bellidiformis)
Photo: Nancy Shepard

I will call out a special thanks to my newly found annual, Mezoo, a type of succulent that thrilled me with its draping form and heat tolerance. I'm definitely going to over-winter this one.

Here is a fact sheet about phosphorus and nitrogen:

https://ag.umass.edu/cafe/fact-sheets/fertilizing-flower-gardens-avoid-too-much-phosphorus

Perennials

Many perennials also thrived with significant cut-back. Salvia, catmint, lambs ear and Shasta daisies all give a second show when I cut them back in early August. I’m more careful about fertilizing my perennials this late in the summer because I don’t want to trick their natural tendency to slow down and get ready for fall. Roses are the exception. They like a nice final fertilization in late August to keep them blooming. I’m also taking notes on which Plant Select specimens have thrived through all this heat and are still holding their own. Something new I learned this year was how to prune lambs ear: cut off the flower stalks. This kept them compact by giving more energy to the lower part of the plant.

Lambs Ear (Stachys byzantina)
Photo: High Country Gardens

Vegetables

My spring cool crops of lettuce, spinach and arugula were terrific and I’m re-sowing those now for a fall crop. If it continues with very high heat in the 90s past August, I’ll drape shade cover over them. 

Watering

It goes without saying that this year summer was hot for a long time. I found myself watering annuals every other day instead of the usual two times a week.

Here's to closing down a summer of gardening and getting ready for fall!