September is a transition month.    The soils are still warm from the summer heat, but the nights are starting to get cooler, and the hours of day light are getting shorter.    This tells plants to do that last bit of growing and doing photosynthesis to make sugars and starches to survive the winter!  Winter? Winters in the Southwest are tough on plants that are genetically designed to withstand brutal heat and blazing sun.  “Seasonal Disorder” does not even start to cover the agony that plants must go through as they lose their life-giving sunlight. But that lies in the future.

September is a Busy Month

September is ideal for planting trees, shrubs, perennials, vines, cold tolerant annuals, bulbs, groundcovers, wildflowers, herbs, fall and winter vegetables,,,, in short, everything!

I could put links to every one of those categories, but here are a few articles on this site that can help you get ready for fall planting in the Southwest:

Planning for Fruit Trees
Bulbs for Spring Bloom
Wildflowers for Spring Bloom

Plan Now

Plan on getting out and doing some planting this fall.    Some work now, and your yard will reward you with a burst of bloom in late winter, spring, and into summer.    It is still hot enough to break a sweat, or worse – get heat-stroke, so be careful out there.  Surviving the Heat.

“Oh shucks,” you think, “Can’t I wait a few weeks?” Not really. If you wait until October to plant, this may not give Southwest adapted plants enough time to grow and become well enough established before the (for them) chilly days of winter.   .

Anytime in September

Fertilizer

Fertilize citrus and landscape plants with a balanced fertilizer for good fall growth.   Exception, do not fertilize palms or trees in the legume or pea family, like mesquite. More on Autumn Fertilizer.

Tomatoes, peppers, and pumpkins can be fertilized with a fruiting or flowering high phosphorous fertilizer for fall fruits.

For roses in Desert Elevations, you could apply bloom fertilizer. You might get some lovely flowers – just don’t overdo it. You want them to have energy for spring as well.

Fall blooming plants, like the native perennial marigolds (Tagetes palmeri, Tagetes lemmoni) could use a bloom fertilizer as well. So could your autumn sage, if you trim it first to get rid of scraggly growth and summer tired tips. More about this below.

Herbs and lawns should be fertilized with a high nitrogen fertilizer for good fall leaf growth.

Also needed for healthy growth, your plants may benefit from some Epsom salts. This helps supply needed magnesium that can become depleated over time.

Planting/Transplanting

Divide and transplant iris, and these 25 other plants.

September or early October is the month to sow native wildflower seeds for spring display.   Here’s a list of some to choose from..

You can plant some of the beauties on this spring flowering bulbs list. Some bulb companies will not ship after October first because of first frost in their areas. And yet you do not want them to ship bulbs too soon because if your bulbs sit in the back of a shipping truck in 100 degree heat they will be cooked. Call the bulb company and talk to them so you can reach an understanding on shipping dates.

Water

Continue regular irrigation of fruit trees, especially citrus, pecan, pomegranate, and persimmon for best production.

Once days are below 100 F, switch to autumn irrigation schedule on your timer. More on Irrigation Schedules.

General Care for September

Deadhead summer-tired salvias and autumn sages for a burst of new bloom. This means lightly clipping them back so the long twiggy growth is removed. This is not a heavy duty rejuvenation pruning.  Think light trim of the ends, not Marine recruit buzz cut. Members of the Salvia genus are rampant growers and need regular trimming.  This advice includes rosemary too (Salvia rosmarinus).  It may not bloom this fall, but a general light tiding up of rampant growth will not harm it.

Avoid pruning fall-flowering plants like the Mount Lemmon marigold (Tagetes lemmoni) and canyon marigold (Tagetes palmeri).  Avoid pruning frost-tender plants like lemongrass, yellow bells, hibiscus, and so many more.  Anything that is tropical.

Keep pulling weeds. Get them before they start to seed. Eight Tips to Eliminate Weeds

Remove any cracked or split fruits from citrus and pomegranates. This is so the plant doesn’t spend more energy on them – instead making other, intact fruit for you to harvest when it is fully ripe.

Lawn Care

Dethatch your Bermudagrass lawn for October overseeding with winter rye grass. If you do not overseed, leave the dethatching until spring. This will help the Bermudagrass survive freezing temperatures.

You could consider getting rid of some of your lawn if you don’t use it all.  One of our friends eliminated their lawn entirely once the kids had grown and gone.  Eliminating Lawn is a topic for another day.. 

Thanks for your visit today.
Jacqueline

Cover image is snapdragon vine – more on vines.

More Monthly Care Tips – pages of them!

The Month By Month Guide offers tips for your landscape (yes even lawns and roses) in every month of the year.  I have a few copies left and am offering them to you – my loyal readers. When you buy from me you get a signed copy!

From the review:

“A great reference book is key to successful gardening in the region where you live. Arizona, Nevada & New Mexico Month-by-Month Gardening takes the guesswork out of gardening for anyone residing in the Southwest. With this book, you’ll know what to do each month to enjoy a thriving garden all year, from January to December. Chronologically organized, this guide is full of critical gardening when-to and how-to advice, along with illustrated step-by-step instructions.

The book’s author is Jacqueline Soule, a Tucson-based gardening expert. She knows this arid region inside and out, and she’s written several articles and books packed with her gardening advice. Arizona, Nevada & New Mexico Month-by-Month Gardening showcases Soule’s expertise in one easy-to-read guide.”

Profits from the sale of this book go to the Horticulture Therapy non-profit Tierra del Sol Institute.  

Legal Notes

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