la

September

Monthly Gardening Tips

David Hillock

Landscape

  • Watch for fall specials at garden centers and nurseries since fall is a great time for planting many ornamentals.
  • Choose spring flowering bulbs as soon as available.
  • Plant cool-season annuals like pansies, ornamental cabbage or kale, snapdragons and dusty miller when temperatures begin to cool.
  • Watch for and control any late infestations of tree webworms.
  • Twig girdler insects should be controlled if large numbers of small branches of elms, pecans, or persimmons are uniformly girdled from the tree and fall to the ground.
  • Begin to reduce the amount of light on outside tropical houseplants by placing them under shade trees before bringing them indoors for the winter.

Vegetables

  • You have all of September to plant cool-season vegetables like spinach, leaf lettuce, mustard and radishes, and until the middle of September to plant rutabagas, Swiss chard, garlic and turnips.

Lawn

  • Last nitrogen fertilizer application of the year on warm-season grasses should be applied no later than September 15. (HLA-6420)
  • Winter broadleaf weeds like dandelion will begin to emerge in late September, which is also the best time to control them with a 2, 4-D type herbicide.
  • If pre-emergent control of winter-annual weeds (henbit, chickweed, annual bluegrass, etc.) is desired in lawns, the application should be completed by the second week of September. Note: Do not treat areas that will be seeded in the fall.
  • Continue bermudagrass spray program with glyphosate products for areas being converted over to tall fescue this fall.
  • Plan to seed bluegrass, fescue or ryegrass as needed in shady areas in mid- to late-September. Fall is the best time to establish cool-season lawns (HLA-6419).
  • White grub damage can become visible this month. Apply appropriate soil insecticide if white grubs are a problem (EPP-7306). Water product into soil.

 

 

 

 

 

Building Healthy Soils

David Hillock

Gardeners want a healthy soil in which to grow plants. This includes ample organic matter, good drainage, sufficient water holding capacity, a rich supply of nutrients and active biological life. Unfortunately, healthy soils are commonly removed from building sites during construction, leaving a new home sitting atop sub-soils, which are often compacted and devoid of nutrients.

Before you can build a healthy soil, you need to know what you have to work with. Soil tests are a great way to determine soil pH, nutrient contents and organic matter content. Simply feeling the soil, running it through your fingers is a good way to identify the texture of your soil. Sandy soils feel gritty and clods break apart very easily. Clay soils are sticky and clods are very hard. A clay soil can be molded in your hands.  Loam soils, the ideal condition for gardening, feel smooth in your hand. They are easy to work.

 

Surface and sub-soil types vary significantly across the state. If you live near a river you may have a very sandy soil, while other areas have heavy clays. Fortunately, the secret to improving soil is the same for both conditions. And that secret is organic matter. Organic matter is a term used to describe living and dead materials derived from plants or animals including, compost, manure, straw, leaves, grass clippings or kitchen scraps. Organic matter enriches soils by providing a surface area where water and nutrients can bind. In clay soils, organic matter loosens structure to improve drainage. Organic matter also invites beneficial organisms into the soil. Soils rich in organic matter are going to have a darker color and many more nutrients.

 

Fall is a great time of year to add organic matter to the garden. It will decompose over the winter months to build healthier soils.

References:

 

  • HLA-6436 – Healthy Garden Soils
  • PSS-2257 – Building Soil Organic Matter for a Sustainable Organic Crop Production

Using Cover Crops to Improve Soil

Lynn Brandenberger

Cover crops are one method of building organic matter levels in production soils while also addressing fertility and weed control issues.  All cover crops will add organic matter (O.M.) which is critical for southern locations such as Oklahoma where O.M. is nearly always very low.  This is due to our warm climate where the microbes that break down organic matter are busy nearly year round.  Cover crops can include a number of different types including legumes and other broadleaf plants and warm season annual grasses such as sudan or sorghum x sudan hybrids.  For our purposes we will discuss both cool and warm season legumes and also the warm season annual grasses.

Legumes can be separated out into two groups, i.e. warm season legumes and cool season legumes.  The reason we use legumes is that they have the ability to fix atmospheric nitrogen in the soil when inoculated with the proper inoculum (bacteria) and they add organic matter to the soil.  Inoculums are generally species of Rhizobium bacteria that soils will have once they have been introduced from planting inoculated legumes.  This relationship between the legume and the bacteria is a true symbiotic relationship meaning that each organism benefits from the situation.  The legume benefits from the bacteria fixing nitrogen from the air into the soil to support its growth and the bacteria benefits because the plant’s roots provide a place for the bacteria to live.

There are many different legumes, but for our purposes we will be discussing only three or four different ones.  Cool season legumes such as crimson clover, Austrian winter pea, etc. are planted and grow during the cool months i.e. fall-winter-spring.  These legumes will tolerate cold temperatures and like all legumes will fix nitrogen into the soil when inoculated with the proper inoculum.  They work well for mid to late spring crops such as tomato or cucurbits that will be planted after the last frost.  It is important to give these legumes enough time in spring to fix nitrogen for the crop that is planted after they are tilled into the soil.  Warm season legumes such as cowpea are planted and grow during the summer.  Cowpea should not be planted until soil temperatures are a steady 70oF often early June in Oklahoma.  Cowpea is very tolerant of high temperatures and drought.  Cowpea works well with late summer and fall seeded crops.  It is best to use a forage type of cowpea such as Victor or Iron-Clay that grows long vines with lots of foliage to shade the soil surface.

Annual grasses such as sudan grass or sorghum x sudan grass hybrids will not fix nitrogen, but are excellent producers of organic matter and will work well for shading the soil surface to choke out perennial weeds such as Bermuda grass.  The thing to remember about these grasses is that they should be brush-hogged (mown) each time they reach a height of 3-4 feet to prevent them from becoming too stemmy.  Also, there will some binding up of nitrogen during the period of time that these grasses degrade after tilling into the soil.  After some degradation nitrogen will again be available for crop growth, but a little extra nitrogen will help this situation if you need to plant quickly.  Winter wheat makes a great cool season grass cover crop.  It can be seeded in early fall to allow it time to establish itself and cover the soil for protection during the winter and early spring months.  As with warm season grasses, winter wheat can end up tying up the nitrogen, but as with all grassy cover crops it does a great job of increasing organic matter in the top soil once it is tilled into the soil in the spring.

General references for cover crops and soil building:

  • Managing cover crops profitably 3rd edition, Sustainable Agriculture Network, Handbook series book 9.
  • Building soils for better crops 2nd edition, Sustainable Agriculture Network, Handbook series book 4.  

 Plants for Poorly Drained Soils

David Hillock

When dealing with poorly drained soils, additions of organic matter address many of the problems faced with garden soils. But sometimes, we run into problem areas in the garden where our efforts have little impact on drainage. Areas where water often drains that are low, have poor soil, or sit at the end of a slope can be such problem spots.

In many urban sites the upper eight inches or so of the soil are in very good condition from years of compost and organic matter inputs, but when we dig deeper, we find compacted clay subsoil. This subsoil has very poor drainage. Plants often struggle to survive in these locations.

 

Our options for managing these sites can be limited. We could excavate the soil to 18 to 24 inches and add improved topsoil, but that can come at a great expense and can sometimes create more problems, and if we have established trees and shrubs growing in the area that is out of the question. Sub-surface drainage pipe can be installed to help pull excess water away from problem areas. And in some cases, we can just build up by installing raised beds. We can also reduce some of the water problems through careful irrigation management, but that is only part of the solution. 

 

Another option, which is generally easier, is to plant plants that don’t mind wet feet. The following plants tolerate poorly drained soils.

 

Trees

 

  • Deciduous holly, Ilex decidua
  • Red buckeye, Aesculus pavia
  • River birch, Betula nigra
  • Bald cypress, Taxodium distichum
  • Black gum, Nyssa sylvatica

 

 

 

 

Shrubs

 

  • Ruby Anniversary™ Abelia, Abelia grandiflora ‘Keiser’
  • Chokeberry, Aronia arbutifolia
  • Summersweet, Clethra alnifolia
  • Buttonbush, Cephalanthus occidentalis
  • Waxmyrtle, Myrica species

 

 

 

Grasses

  • Switchgrass, Panicum virgatum
  • Inland sea oats, Chasmanthium latifolium
  • Feather reed grass, Calamagrostis arundinacea
  • Prairie dropseed, Sporobolus heterolepis
  • Sedges, Carex species

 

 

 

Perennials

  • Yarrow, Achillea millefolium
  • Beebalm, Mondard didyma
  • Milkweed, Asclepias spp.
  • Iron weed, Vernonia lettermanii
  • New England Aster, Aster novae-angeliae

 

 

 

 

 

'Blond Ambition' Blue Grama

Through the years, ornamental grasses have been bred and selected for special traits just like breeders do with flowering plants. Breeders select grasses for blade color, blade variegation, cold and heat hardiness, shape, size and flower. One of the newest ornamental grass available on the market is Bouteloua gracilis ‘Blonde Ambition.’ Bouteloua gracilis, blue grama grass, is a warm-season, native grass that can be found throughout the Great Plains. Blue grama and buffalograss were the major native grass species of the short grass prairie.

‘Blonde Ambition’ blue grama is a native grass with a strikingly new look. It flowers in mid-summer through fall. The flower starts with a chartreuse color that changes to a blonde seed head as it ages. The flowers have been described to be “eyelash-like”. The flower doesn’t sit upright on the tip of the stem, it sets horizontal, which adds to the unique beauty of this grass. The blonde seed heads will remain on the plant through winter providing additional ornamental interest in your landscape.

 

‘Blonde Ambition’ is a long-lived, warm-season perennial grass. The leaves are a fine textured gray-green ranging in height from 12 to 18 inches, but the flower rises above the foliage to a height of about 2 1/2 feet. The cultivar ‘Blonde Ambition’ was selected for the more robust and larger flowers than those on the typical blue grama. Most grasses prefer full sun and this one is no different. It will tolerate most any soil so long as it is well-drained. This is a drought tolerant grass and is very cold tolerant so it will only need to be watered occasionally; however, the plants will grow faster and look their best when irrigated.

Sources for Fruit & Pecan Nurseries

Becky Carroll

 Listed below and in the attached links are some possible resources for tree fruits, grapes, small fruits and pecan.  This list is not intended to be all-inclusive, exclusive of other potential sources, nor an endorsement of any of the plant material providers.  The intent here is to give county educators a fast source-list of nurseries that carry nursery stock.

Order early for good selection. Place your order for delivery at ideal planting time. Most fruit trees and pecans can be planted during mid-February to March. Please make sure that the cultivars chosen are adapted to the Oklahoma climate. Choose trees or plants that are disease resistant. Also make sure the chilling requirements are suitable for Oklahoma. Don’t purchase items advertised as “low chill”. They may break bud too early in the winter and bloom before the risk of frost has past. For information on variety selection, there are several fact sheets available in the following link.

 

 

 

Document Actions