This blog is about growing tropical-looking plants in the Phoenix, Arizona area



December 11, 2016

How to plant petunias in Phoenix, Arizona


It's December, and I'm planting petunias. Yes, you plant petunias in November and December in the Phoenix, Arizona area. I've lived here for over twenty years, but I grew up in Minnesota, and it still feels kinda weird. I've tried to plant annuals here as early as September, or October, but found that it was still too hot, and they mostly all died. So if it's not actually cold enough outside to wear a shirt, wait a bit.

Yesterday in a moment of enthusiasm I bought two kinda sad-looking petunia plants at a nursery in downtown Phoenix. In a perfect world, I wouldn't have bought petunias that were quite so elderly, but it's what I have today, and I'm planting them.

The first thing to do (especially with annuals that have gotten all straggly) is to give them a haircut. I cut this one back severely, and am hoping that it still has some life left in it. Petunias are strong growers, and with the right care, I think it will. The salesman at the nursery told me that it wouldn't grow much bigger, but I could tell that he didn't know about petunias, which can grow over a very large area in a matter of months. So it will start out sad and puny, and once it starts growing, it will be beautiful, and full of flowers.

Moisture crystals and slow-release dry fertilizer in the planting hole for the petunia

The first step is to slow down, and take your time. I'm a big believer in digging a "$100 hole for a $50 tree" and I apply it to even the tiniest plants in my garden. They all deserve the royal treatment. So I start by digging a hole that's too big, and pouring in some potting soil.

The next thing is a couple of invisible tricks that make a huge difference for annuals - dry slow-release fertilizer, and polymer moisture crystals. Moisture crystals are sold over by the houseplants, and they're little tiny pieces of plastic that absorb water and swell up. I sprinkle just a tiny bit at the bottom of the hole. Annuals love water, and will die if they dry out, so the moisture crystals are awesome for them. You have to be careful not to get them wet, so I put them in a little zip lock bag, which the Woman in my Life has kindly labelled for me.

The next step takes the most patience - watering the hole and letting it soak in. At least fifteen minutes. I go and make myself some decaf or something. Or I write in this blog, which I'm doing now. I noticed that the area that I want to plant this petunia is dry dry, so I'm doing to absolutely sure that the ground is moist before I put the plant in. If you put a plant like this in a dry hole, the water will be sucked away from the plant, which is not good. Annuals love water, so you can be as generous as you want. Even in the winter the desert air is dry, so go ahead and give the plant a shower!

Planting hole watered and soaking in, before the plant is place there.

I have a three-gallon lightweight plastic watering can (don't even think about using a heavy metal one, carrying three gallons of water is heavy enough!) with a rose end that I use to hand-water the annuals all winter. My automatic watering system is off until late January, so the annuals will need personal attention. I had a little bit of water-soluble fertilizer in and give them a little bit when I water and shower them. They take in the fertilizer through their leaves also, you know! You can water them every day through the winter and early spring, as much as you want. You don't have to water them when it rains, which it usually does in late December and early January here in the Sonoran Desert. But don't worry about over-watering them! Water them all you want!

Yes, I'm absolutely crazy, I know. But to me, plants are babies, and that's why you get them at a nursery. You don't just leave them out to fend for themselves, you care for them, give them what they need when they're tiny. If you have the right heart for this, they will be fine. They will live, and grow, and make you proud!

Petunia planted on December 11th in Phoenix, Arizona, and the space it will fill until April or May, when it will die back from the desert heat.

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