SMOOTH BROME: THE PROBLEM

Smooth brome or smooth bromegrass (Bromus inermis) is not a native grass. References suggest it was introduced into the United State from Hungary in about 1884. Smooth brome is a cool season turf grass (rhizomatous) and produces a dense sod. It is deeply rooted, and thus resistant to temperature extremes and drought.

Smooth brome is considered a very good pasture grass for livestock and was widely planted around the turn of the previous century. It is also widely planted as a habitat or rehabilitation grass, as it is a fabulous soil binder and will solidly establish itself on otherwise difficult sites.

As an additional benefit, the dense sod produced by smooth brome is extremely good at preventing infestations of noxious weeds such as the various knapweeds, thistles, and whitetop (Cardaria draba).

HOWEVER, this plant is essentially invasive. In sites that have the correct soil and water, it will establish itself very swiftly, forcing out the native grasses. This is particularly true in sites with a history of excessive disruption, either due to over-grazing or excessive mowing. (The Ranch has experienced both.)

It is possible to eliminate Smooth Brome by techniques such as glyophosphate application and disking. However, such techniques tend to be very counter-productive in the Methow Valley. The issue is that any level of soil disruption is immediately followed by rapid colonization with the REAL nasties (knapweeds, thistles, toadflax, whitetop, hawkweeds and so on).

In additional support of a more gradual approach, several historical attempts were made in the DFW area slightly north of the Ranch to aggressively eliminate non-native grasses, and the result was conversion of a non-native grassland into knapweed habitat (which is definitely a step in the wrong direction!).

At this point, the plan is to take a more gradual succession-like approach as described below.

In a natural biological succession (for example, a fire-succession) the first group of plants are those that can survive the existing conditions successfully and energetically. These plants then provide shade and nutrients to further generations of plants that mature underneath them. When these further generations of plants mature, typically the original succession plants begin to reduce in number

An excellent example of this is snowbrush, Ceanothus velutinus. snowbrush is a fire succession plant, requiring fire for its seeds to sprout. After fire, the snowbrush grows quickly and aggressively, creating huge thickets. snowbrush is a nitrogen fixing plant, and these thickets are shaded and moist. Thus, the next generation of plants (subalpine fir, ponderosa pine, and the like) grow up underneath the snowbrush. Eventually they will mature and shade out the snowbrush.

Thus, the plan with the smooth brome is to try and plant through it - establishing plants (particularly woody plants) that will eventually mature and shade it out. Now, this is somewhat easier said than done, because the succession plants need to be able to out-complete the root system of the smooth brome.

This was the Fall planting 2017 list:

Douglas Hawthorne (Crataegus douglasii) - planted 2017 Serviceberry (Amelanchier alnifolia) - planted 2017

This was the Fall planting 2018 list:

Quaking Aspen (Populus tremuloides) - planted 2018

Mackenzie Willow (Salix prolixa) - planted 2018

Scoulers Willow (Salix scouleriana) - planted 2018 

This was the Fall planting 2019 list (after the deer fence): Snowbrush (Ceanothus velutinus)

Quaking Aspen (Populus tremuloides)

Chokecherry (Prunus virginiana) 

Ponderosa Pines (Pinus ponderosa)

<2020 Ordering was skipped due to COVID>

This was the Fall planting 2021 list (this was planting the boggy spot):

Quaking Aspen (Populus tremuloides)

Chokecherry (Prunus virginiana)

Serviceberry (Amelanchier alnifolia)

Fall planting 2022 (may not happen due to the early snow)

Ponderosa Pines (Pinus ponderosa)

An overall summary is that only chokecherries, serviceberries and ponderosa pines (and Russian olives!) have shown any real success. Everything else just struggles.

The plantings in the smooth brome have been, BY FAR, the most challenging plantings on the ranch. In an nutshell, the brome simply out-competes everything (except Russian olive, Elaeagnus angustifolia). (As an aside, Russian olive isn't native and isn't desirable either, as it too can be invasive. However, for the moment, it is the only plant providing some habitat diversity within acres of smooth brome.) Note also the fact Russian olive CAN outcompete the brome at least says it is possible for something to outcompete the brome ...

During the summer of 2022, some significant success was achieved by surrounding plants with a ring of landscape cloth. Particularly interesting, was the discovery that plants with rings of landscape cloth that were NOT irrigated outperformed plants WITHOUT rings of landscape cloth that were irrigated. More simply, all the irrigation was doing was watering the brome. (The good news here is that this means we can shut down irrigation in the brome area, which would be fabulous for water management.)

Also interesting was the more general observation that plants tended to grow to a size where the crown was approximately the size of the landscape cloth ring, and then stop. Again, this supports the idea that the problem is the brome, not lack of water in the habitat.

The good news here is that we now think we understand the problem. The bad news is that anything that we want to survive in the brome (other than Russian olive) is going to need to be supported by landscape cloth rings until it gets to some unknown size.