Throgmorton: September Garden Tips

Sometime this month we’re going to have a freeze. That’s the end of most annual flowers and the vegetable garden. After the freeze we’ll have beautiful weather. The days won’t be too hot and the nights will be cool. It’s time to clean up the frozen plants. It’s time to get things ready for winter and next spring.

After the first killing frost, dig the vegetable garden. Doing it in the fall allows you to add more nutrients to the soil. Add compost from the bin. Chop up debris as you clean out other garden beds. Add it to the garden to breakdown during the winter. Leave the top of the garden rough. This catches more winter moisture and prevents the soil from blowing away.

Pine trees naturally lose needles in the fall. Some pine like Austrian and Ponderosa pine, lose needles every two or three years. Other varieties like Bristlecone and Limber pine lose needles every fifth year. This time of year the inside needles turn brown and drop. Add them to garden mulch to acidify the soil.

Leave the last flowers on your roses. The petals will fall and a fruit will form. Many of the hardy shrub roses have colorful hips or fruit. The hips add fall and winter interest.

Hybrid tea, grandiflora and grafted roses do need winter protection. Once the ground has frozen, in a couple of months, cover the graft union with six inches of compost or mulch. You can still leave the hips at the top of those roses.

This is a great time of year to plant and transplant. The soil is still warm to promote root development. The days are cooler and less shocking to newly planted plants. Divide perennials that have gotten too big. Don’t divide or move ornamental grasses this time of year, wait until spring. Add new shrubs or trees to landscape beds. Plant clusters of spring flowering bulbs for an early blooming show next season.

Get on the schedule to have your sprinkler system winterized. The early, hard freeze last year damaged a lot of systems. The outside parts of the system need drained and the other parts need the water blown out of them.

Tom Throgmorton, of Throgmorton Plant Management, can be heard on KUNC, 91.5 FM, every Saturday morning at 7:35 and 9:35 a.m.

Originally published on September 23rd, 2011.