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In the mornings, at this time of year, our road cuts, orchard, and especially the meadow area, are awash in a sea of yellow.

Rough Cat’s Ear (Hypochaeris radicata)

This cheery swath of yellow is Hypochaeris radicata, commonly known as Rough Cat’s Ear, False Dandelion, or Flatweed.

One of the most notable features of these flowers is they are only visible in the morning hours.

In the mornings, these flowers seem to be everywhere

However, by early afternoon on a sunny day, there’s not a bloom in sight.

The flowers need at least an hour of sunlight to open, and don’t open on rainy days.  By staying closed during bad weather the flowers are able to conserve their pollen.

While the flowers are open in the morning it looks like we have a herculean weeding task ahead of us, but then by the early afternoon, the problem just seems to magically disappear.

Once open, it takes at least three hours for the inflorescence to close again

That is until the flowers open again.

Rough Cat’s Ear is a perennial member of the Asteracae family, and native to Europe, North Asia, and North Africa. This species can easily be distinguished from true Dandelions by its hairy leaves.

The leaves of Rough Cat’s Ear are covered in short, sparse hairs

Dandelion leaves are smooth.

Here, on the farm, with scant else in bloom, these flowers seem to be a favored late summer forage for our honey bees.

Honey bee on Hypochaeris radicata

Staring at the flowers this morning, it seemed that at least 1 in 4 flowers were being exploited for their pollen. One honey bee after another would briefly alight on an open flower, and then quickly move on to the next.

This bee comes in for a landing…

Standing still in the middle of all these blooms you find yourself surrounded by hundreds, if not thousands of honey bees.  Even if you can’t easily see them without stooping down, you can hear them!

…while this bee takes off for the next flower

The majority of the bees I saw this morning already had their pollen baskets packed with vivid orange pollen.

Every bee visiting these flowers was carrying the same color pollen

It will be interesting when we check our hives this weekend to see just how much of this vibrant pollen is being stored.

Watching the bees forage, it was clear the pollen from these flowers is orange, not yellow

The bees aren’t the only ones that find value in this plant. In its native range this plant serves as a larval food plant for some species of Lepidoptera, including Depressaria badiella, and Cucullia umbratica moth species.

The young leaves are edible, although reportedly quite bland, and may be eaten raw, or steamed. Older leaves become too fibrous and tough to be considered of any culinary value. The taproots of Hypochaeris species are also apparently edible, and when roasted and ground, may be used as a chicory-like coffee substitute.

Hypochaeris radicata is classified as a moderately invasive species in California

According to Calflora, it’s also a moderately invasive weed along the coast and inland valleys of California. In Washington State this species is classified as a Class B noxious weed.  Although we’ve been quite ruthless striving to eliminate some invasive plants from the property, like the French Broom, I personally have a difficult time being very angry at this plant, at least at the moment.

Bees prefer to forage among drifts of the same flower color or type

Our dry summer weather seems to help keep this plant somewhat in check, and mostly we find it growing in poor soils, in disturbed areas.

It’s difficult to loathe a plant when it clearly provides some benefit for our pollinators

Regardless of its invasive status, I’m not particularly fond of weeding, so I often strive to find any excuse I can to avoid that chore. This morning my excuse was the bees.

This bee appeared to be gathering a little nectar

Is it the best bee forage we could grow? No. In fact, Hypochaeris is considered to only be a minor pollen source for honey bees along the coast.[1] Its nectar yields are even less significant.

As much as the bees seem to enjoy them, it’s difficult to deny that Cat’s Ears have a dark side. In some areas they are so invasive that they are considered a significant agricultural pest, capable of inhibiting the growth of, or smothering, intentionally cultivated species.

The densely formed basal rosettes of leaves also can displace and smother native annual species of plants.

A few plants don’t do much harm, but the flat rosettes of leaves, en masse, can smother the soil

The deep taproots of Cat’s Ears may provide a competitive advantage to this species in dry climates, and in non-irrigated areas.

Hypochaeris radicata has also been determined to be allelopathic, and may slow or prevent the growth of native species, especially grasses. [2,3]

Perhaps the most sinister side of Hypochaeris radicata is when consumed as the principle forage on dry pastures, it has been shown to cause Australian Stringhalt in horses. [4,5]

The majority of Hypochaeris radicata plants growing here are in heavily disturbed areas, either where we cultivate the ground, or where our ground-heaving gophers have been churning the soils.

The toe of the slope below the orchard has seen a lot of gopher activity this season

We’ve been controlling gophers in the orchard and gardens, but at the foot of the slopes, the gophers have obviously been running amok, which can cause dormant seed to be brought to the surface.

Cat’s Ears grow and persist the best in areas that are repeatedly disturbed, so the first step in controlling the spread of this species is to minimize disturbance.

Early hand digging of young plants in the spring months, including the taproots to prevent resprouting, should help with control.

Mowing and cutting, however, is not recommended, as it encourages the formation of additional flowers, and thereby increases seed production.

However, if we remove all of these late summer blooms from the farm, there will be even less for the bees to forage on this time of year.  As such, before we remove them, we need to decide what to replace them with.

Honey bee on Hypochaeris radicata

Fortunately, there are a few honey bee-friendly native species that will bloom in the late season here. We already have a few stands of Western Verbena (Verbena lasiostachys) growing around the property, and bulk seed is readily available. so we can easily plant a lot more.

Other honey bee friendly alternatives include Monardella sp., Coyote Brush (Baccharis pilularis) which is a good source of both pollen and nectar, Telegraph Weed (Heterotheca grandiflora), and our native California goldenrod (Solidago californica).

Next season we hope to offer these bees a more favorable forage

For this season we’ll leave these plants alone. We’re hesitant to remove anything that qualifies as forage at the moment, as one of our hives is already showing weak activity at the hive entrance. When we do a long-overdue hive inspection this weekend, we’re not expecting to find much in the way of food reserves in any of our colonies.

However, this fall as we plan our native plantings for next season’s blooms, we’ll start replacing this species with more suitable native plantings that will provide forage, not just for the honey bees, but for all of our pollinators.

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[1] Rose, Jeremy. 2008.  Beekeeping in Coastal California – With a Monthly Tutorial and Varroa Management Program.  Published by the California Bee Company, LLC.

[2] Aarssen, L. 1981. The Biology of Canadian Weeds. Hypochoeris radicata L.  Canadian Journal of Plant Science. 61(2). 365-381 p.

[3] Turkington, R., and L. Aarssen. 1983. Biological Flora of the British Isles. Hypochoeris radicata L. (Achyrophorus radicatus (L.) Scop.). Journal of Ecology. 71(3). 999-1022 p.

[4] Huntington PJ, Jeffcott LB, Friend SC, Luff AR, Finkelstein DI, Flynn RJ. Australian Stringhalt–epidemiological, clinical and neurological investigations. Equine Vet J. 1989 Jul;21(4):266-73.

[5] Araújo JA, Curcio B, Alda J, Medeiros RM, Riet-Correa F. Stringhalt in Brazilian horses caused by Hypochaeris radicata. Toxicon. 2008 Jul;52(1):190-3. Epub 2008 May 29.