Why are so many flowers yellow?

I’ve been out in the garden this morning, picking some almost-ripe tomatoes and bringing them in to their usual place on the piano, to ripen. As I was doing this, I realized that an awful lot of flowers are yellow. This intrigued me and I started to wonder why that is.

We live in a time of miracle and wonder, as Tom likes to say. Remember the days when we had to go to the library to find stuff like this out? Or to the World Book Encyclopedia? We had a shelf of those that my parents bought in 1964. As a child, whenever I was bored, I would go look through them. Oh gosh, remember boredom? Does that exist anymore?

Heavens, before I croak out something like “well, sonny, back in my day,” let’s move on, shall we? What I meant to say was that you can go to Google Scholar and type in ‘why are so many flowers yellow?’ or ‘color in flowers’ and get to read all kinds of interesting scientific papers, most of which don’t really answer the question, only pose more questions, but that is why we are never bored anymore, right? All hail the Google rabbit hole.

ANYWAY. It’s actually hard to find the percentage of yellow flowers in plants. I did see that early spring plants are often yellow, which is a way to signal early food for pollinators. Wait, let me back up. Why would flowers have color to begin with?

Fossils suggest that early flowers didn’t have much pigment, but rather were a dull yellow or pale green before they evolved over 100 million years ago to produce colors. It is assumed that they evolved that way to attract pollinators. Apparently many plants have evolved colors that match the specific visual systems of different insects or birds.

You might remember that bees (and many other pollinators) have compound eyes. Our own eyes can only detect three colors - red, blue, and green. Bees cannot see red, but they do see blue and green, and also UV light - that means they can see colors we cannot see. Many flowers have ultraviolet nectar guides, a sort of pattern that we cannot see, that are like runways lighting the way down to the inside of a flower.

Bees have awful long-distance sight, so they use scent rather than sight to find nectar, but those compound eyes provide amazing up-close vision, allowing them to see these specific colors and patterns once the smell has lured them to the flower.

Color we see in flowers is the result of reflected light from various plant pigments. These pigments can be anthocyanins, compounds that make autumn leaves red, or blueberries blue. Flavonol pigments make yellow and chlorophyll pigments make green. There are flavanoid pigments that are colorless to us, but also absorb UV light and make colors available to bees and other pollinators.

Therefore, a bee balm that appears red to us might appear white to an insect. Yellow and white flowers (to us) may appear blue to insects. In the course of my research, I also learned about flowers such as borage or fleabane, which turn different colors over a season (like from pink to blue), are doing so to signal to pollinators which flowers are new and have a lot of nectar, and which are too old to produce (thank you to the University of Vermont for much of this post’s information!).

Native bees have evolved to drink from the blossoms of the plants that evolved with them, which is why it’s a good idea to have a percentage of your plants as natives. But they will readily drink from exotic species, and honeybees will forage on almost anything - it is a generalist species. However, there is evidence that bees prefer (what appears to us to be) blue and white flowers. Birds tend to prefer (what appears to us to be) red flowers. Have you ever noticed (I have!) that many red flowers seem to have yellow centers? Could that be those UV light patterns directing bees to the flower, even though it is red?

Evolution is crazy, yo.

I couldn’t find any solid information about yellow flowers in particular and why it seems that nature makes so many flowers yellow (it could just be a coincidence that I’m seeing so much yellow this time of year). But I’ll leave you with this paragraph of an abstract which I found, entitled ‘Pollinator Preferences for yellow, orange, and red flowers of Mimulus verbanaceus and M. cardinalis’ which are both monkey flowers. It is authored by Paul K. Vickery, Jr of the University of Utah.

“Red, orange, and yellow morphs of Mimulus verbenaceus and M. cardinalis were field tested for pollinator preferences. The species are closely similar except that M. verbenaceus flowers have partially reflexed corolla lobes, whereas M. cardinalis flowers have fully reflexed corolla lobes. On the basis of over 6000 bumblebee and hummingbird visits, highly significant (p < .001) patterns emerged. Yellow, which is the mutant color morph in both species and is determined by a single pair of genes, was strongly preferred by bumblebees and strongly eskewed by hummingbirds in both species. Orange and, to a lesser extent, red were strongly preferred by hummingbirds but eskewed by bumblebees in both species. Thus, strong, but partial, reproductive isolation was observed between the yellow mutants and the orange- to red-flowered populations from which they were derived. Color—yellow versus orange and red—appeared more important than shape—partially reflexed versus fully reflexed corolla lobes—in determining the preferences of the guild of pollinators in this particular test environment for Mimulus verbenaceus and M. cardinalis."

So it would seem that native bees prefer yellow, at least on those particular flowers. So interesting!

Other news:

*Tom and I watched three juvenile Cooper’s Hawks fledge over last weekend. They hung about in our yard and on the nearby power lines, together in a group, for quite a while. It was an amazing thing to see.

*Highwire coffee, a local roaster and the place I go to collect coffee chaff for chicken coop and garden purposes, has just been awarded a seal by the Rodale Institute for their organic ‘Conscientious Objector’ line of beans. We think Highwire makes truly delicious coffee and we are happy they are being recognized for the work they do with organic farmers. Their coffee bags are also compostable which is a huge bonus.

*Just another urging to go see The Biggest Little Farm if it is playing near you. Tom and I saw it again this past weekend, and it’s just such a great movie.

*Shoutout to the Merritt Horticulture students from LH1 who came by for a garden tour and talk last night. What an amazing group of people, with some amazing projects and ideas in the works, and many of them already ‘farming’ just like I do here. It was great to hang out with like-minded folks and plant nerds again. I’ve missed the Hort department and was super glad to be a part of it again for a night!

*Did you know I put ‘tags’ at the bottom of each post? This is so if there is a subject that interests you, such as pollinators, you can click on that tag and see everything I’ve ever written about pollinators. It’s not a fail-safe program; the other day I tried to find Tom’s instructions on how to build our garden trellises, and I’m still looking (you should be able to find it under the ‘projects’ tag, but clearly I didn’t tag it that way). You can also go to the Archives and search a word or a term, like ‘cooking,’ and find all the recipes I’ve talked about.

*The harvest has begun. Cucumbers, beans, tomatoes, and some hot peppers are starting to come ripe. This caused me to see that I was not prepared to start preserving the harvest. Here is your reminder to make sure that you have plenty of mason jars, lids, rings on hand; labels, pickling salt, pectin, etc. Here we go!!!

It Happened AGAIN

Hundreds of shallots, hanging on new racks in our dining room, looking beautiful. We had grown them from October to May, cured them over the chicken coop, tied them into bundles. Given many away. Been cooking with them regularly. Two days ago, a black aphid hanging out at eye-level on the wall by the piano; '“hm, what’s an aphid doing in here?” then yesterday, passing by the rocking chair which is underneath the hanging shallots, noticing the floor littered with black things. I look up. The shallots are covered, simply covered, with allium aphids.

We cut them down, we take them outside, we clean the floor and the walls and the rocking chair thoroughly. We sit and talk, what to do now, can they be saved. Allium aphids will eventually eat the bulb, in storage, if the greens are gone. We decide to chop them all up and freeze them. In the process of that, noticing them everywhere, in the bulbs too. Some bulbs are already rotted. Frustration and annoyance and pure disgust. We throw them all in the green bin, unwilling to put them in our compost and possibly breed more aphids.

Neotoxoptera formosana, the onion aphid, or allium aphid. Dark red to black. They do not lay eggs; the females give birth to pregnant females. Populations increase very rapidly. The aphids carry viruses and can cause disease in the plant. They prefer juicy green leaves but will eat bulbs in storage.

image credit: influentialpoints.com

So. Failure. Again.

What happened? I was too angry and disappointed at first to think about this from a logical standpoint, but after a good sleep and some time to calm down, I can start to figure out the chain of events that led to this.

Much like the disaster of Chernobyl (have you watched this on HBO yet? SO GOOD), there wasn’t just one thing that caused the problem, but rather a group of things.

One, the soil was probably not sandy enough or loose enough to keep the bed well-drained. Two, I grew them alone, without another crop - intercropping with a flowering herb or annual (such as clover) would have brought more predators down in to the bed. Three, we had a hot spell (a week of temps near or at 100) in April that caused the plants to start bolting, which caused me to think (reasonably) that the plants were done growing. Four, I didn’t remove the irrigation the last 2-4 weeks of growing, which would let them dry out in the soil before harvest. Five, I harvested them too early, with too much green growth still on them (it’s hard to leave them in the ground long enough, with the summer garden needing to go in). Six, I didn’t let them cure long enough, and I had so many that they were crowded in the curing space (preventing good airflow). Seven, and final nail in coffin, I brought them into the house where predators couldn’t keep the aphid population in check. If even one aphid was left alive on a stalk, the population would grow exponentially until finally covering the shallots completely.

Our garlic crop was also compromised by these same mistakes, though we haven’t yet (knock on wood) noticed an aphid explosion. The Spanish red garlic came out ok, though the size of the bulbs and cloves is too small. The German red garlic came out ok (though very small), but somewhere in the curing step, about 90% of them started to soften and rot, and we were able to keep only about 10%. Not ideal.

The amount of expense, and really TIME, that it takes to grow these crops is huge. This is not a small loss. It is extremely frustrating. At first I said to Tom, maybe we just can’t grow them here, maybe they just take too much time and we’ve had too many failures, maybe our first few successful years were just luck? But after figuring out the list of reasons why they failed, I see that I can do better growing them. I can’t do anything about the weather, but I have a plan for that too.

So, this Fall, here’s what I’m going to do. One, order seed bulbs directly from the grower (Filaree Farms has been recommended to me). Two, I’m going to plant them later, in November rather than October. Three, I’m going to plant less of them, only one bed for shallots and one bed for garlic. Four, before I plant, I’m going to break my no-till rule and make sure the soil is loose and that I’ve added plenty of compost and maybe some grit to increase drainage. Five, I will interplant with crimson clover, which should add a place for the good bugs to proliferate. Six, I will plant them in a place that has more shade in April (and maybe cover them too), and not in the place where I want to put tomatoes next year, which need to go in May 1, which is part of Seven, I will leave them in the ground until June. Eight, I will remove the irrigation lines for the last month of the growing season. Nine, I will make sure they are totally ready before harvesting. Ten, I will cure them differently, in a different place, allowing more airflow and more time (this will be difficult because they need to cure in shade). And finally, I will allow them to cure for longer, and inspect them thoroughly, before I bring them in the house.

Having a plan makes me feel better, but I’m still extremely pissed and sad about the fact that I’m going to have to buy shallots for another year.

I’ve been preparing a talk for some students that are coming to visit this coming week, and it has become clear to me that I need to talk a little bit about failure, because it happens. Even when you’re doing everything right (which I wasn’t this time), some things just don’t work, and it’s hard to figure out why. It can be difficult to weather those failures and still keep going. And so I’m interested; how do all of you, my readers, handle these disappointments in the garden? If you have a story to share, please do so in the comments.

Garden Hurdles

There’s a show on the BBC that I absolutely love, called Gardener’s World. It features Monty Don, who gardens a plot of land called Longmeadow. The garden is in Herefordshire, west of the Cotswolds. I can’t get this show on my TV, but every week some intrepid YouTuber puts it up on his channel. Invariably it is taken down within hours, as it of course is put up without permission. If I catch it just right, I can see the whole episode. I ALWAYS learn something. And I love looking at the gardens, both Longmeadow and the ones the hosts visit, and learning how different people do things.

In a recent episode, Monty was saying how they had had a lot of rain, and it caused all his border plants to flop into the paths, which caused anyone walking there to have soaked pants in seconds, and of course the plants were getting trampled. So he was using hurdles to prop them up, off the path. Ding ding ding, my brain was singing, this is what you need, Elizabeth! So of course I texted Dad immediately. “You have any of that French Broom laying about, from the garlic rack project?” and one thing led to another, with Dad taking a trip to a local open space, braving the thick stands of poison oak, chopping down more broom, and then making me five hurdles out of it.

I love ‘em and I could use another 20, honestly. I see endless uses for them. Originally these weren’t used in the garden, however. The UK have a long history with hurdles. They were used as a temporary pen for sheep, for shearing, or tagging, anytime the farmer needed to corral some livestock temporarily. They had to be lightweight so that the farmer could carry several at a time on his shoulder. They had to be flat for easy storage. They were often made from coppiced wood (another ancient term which no one uses anymore), which was a method of cutting down fast-growing trees to a certain height every year, using the cut wood for farm projects, and allowing the tree to regrow for the next year. Willow was a common wood used for this purpose, or hazel. Eventually the advent of modern sheep containment overtook these old ways of doing things, and folks used their old hurdles for garden fencing. Now artisans make them for high-end gardens, often woven, costing a whole lot of money.

I found an interesting website for the Heritage Crafts Association in Britain, whose President is HRH the Prince of Wales! The association explores all kinds of crafts in the history of the country, reports them alive and well or endangered (as hurdles are), and discusses the history of the items and any other interesting tidbits. If you’d like to read more about hurdles (and I think you should, it’s fascinating), you can see that website HERE.

Their mission statement reads “The Heritage Crafts Association supports the 2003 UNESCO Convention and its goal of safeguarding traditional craftsmanship by supporting the continuing transmission of knowledge and skills associated with traditional artisanry – to help ensure that crafts continue to be practiced within their communities, providing livelihoods to their makers and reflecting creativity and adaptation.”

I love this. I went down a very interesting rabbit hole looking at all the different traditional crafts that are endangered or the knowledge of creating them has become extinct.

On the more modern side of things, Dad created a series of YouTube videos to show how to make these,. If you’re looking for a summer project for your garden, you can find that series HERE. I imagine that there are lots of different kinds of wood or supplies that can be used to make these.

Morning Fruit

One absolute delight this time of year is picking fruit for breakfast. I go out around 6 am to let the chickens out anyway, so from there it’s an easy detour to whatever fruit patch looks most promising. It’s hard to think of something better than a handful of fruit to go with our eggs or cereal.

We’re finally at a point where a lot of our fruit vines/bushes are reaching the maturity to produce more regularly, or maybe we’ve just learned how best to care for them. Take that statement with a grain of salt, please, because we lost two fruit trees this year, the Santa Rosa plum and the Asian pear. The plum blossomed beautifully and then just died, I can’t figure out why. The pear died after I transplanted it too late (I was trying to give it a place with more sun). I also think we will be losing our peach after this season; it’s quite old and very damaged. Over the last five years, I’ve planted and lost two cherry trees and six raspberry canes. So let’s just say that the learning curve has been steep!

Our current fruit inventory consists of two apple trees (one ancient and still bearing, one very young and just starting out), one peach (ancient, and as I said, on its way out - I’m thinking of replacing it with a mulberry), one ‘Panache’ fig (growing to a monstrous size), one quince (ancient and produces no matter how we hack it up), one naval orange (still very young and not yet producing), one elderberry (very young, still not producing), two Arbequina olives (in pots, producing just enough olives for us), strawberries in gutters and in the ground, eight blueberry bushes which are about five years old, ten rhubarb plants, one native huckleberry, and a thornless blackberry. I’ve just ordered six marionberry plants, which are a hybrid blackberry; we fell in love with marionberries in Oregon a couple of years ago and have trouble finding them at the markets.

We finally found the best location for strawberries in our garden; it has taken years and many failed plantings to figure that out. The strawberries in gutters, and the ones growing in the ground beneath those, are doing just great. They get a couple of hours of direct early morning sun, and then are in shade the rest of the day. We don’t have irrigation going to them, so I water them every day, and feed them with fish emulsion every month. Keeping them mulched has helped with slug pressure, as is the fact that they are right next to the patio, in a place slugs rarely visit, and most are high off the ground. I had about 25% failure rate with the plugs, but I’ve been replacing them with runners from the other strawberries. What this has done is mix up my record-keeping; I no longer know which berries are which variety, but that really doesn’t matter. What matters is we are getting a large handful every day.

I’ve got several different high-bush varieties of blueberries, and they’re also doing great this year, I think because I pruned them hard last winter, taking out all of the older wood and leaving only young canes. Some of the young canes aren’t producing yet, but will next year. They are on drip irrigation and mulched heavily with coffee chaff (low-fertility organic matter is key for blueberries). I do not like to add sulfur because it hurts soil life, but about two years ago I did add a little blueberry fertilizer. The native huckleberry is also doing quite well after a rather severe pruning last winter. We all tend to stop and graze from that shrub throughout the day, as the berries are incredibly small and it takes an awful lot to make a handful.

Our thornless blackberry vine was a freebie from a neighbor. It likes where it is planted (morning and late afternoon sun, shade in the middle of the day) and is trained up on our fence. However, for years it suffered deer pressure because it is outside the fence rather than inside. I finally got that area planted up with ornamentals (mostly Leonotis leonurus), and that has reduced the deer pressure on the blackberry. It is loaded with green berries right now, I can’t wait to start eating those. I’ve never fertilized it, but it is on drip irrigation and is heavily mulched with wood chips, plus it sits next to one of our worm bins so it probably gets some leachate from that.

Even with all these plantings, I still have to buy fruit any time I want to make a pie (except maybe apple), or when Tom makes jam - we can never get enough! As you know, fruit trees take years to produce a substantial crop, so adding new trees a little at a time makes sense. Also planting trees and vines that will do well with the changing weather is smart. As I said up top, I’m thinking of replacing our peach tree with a mulberry rather than another peach. There are many reasons for this, and one is the weather. We all have to start thinking ahead with regards to climate change - what is our weather going to be like in five years, or ten? Most peaches need a lot of chill hours, and it’s likely that we’ll get less chill hours here in the future (and we don’t have that many to begin with). Peaches also need spraying for peach-leaf curl, which is a fungus, and the copper in that spray, though technically ‘organic,’ harms soil life. I don’t want to spray anything in my garden that harms soil life. We love having fresh peaches off the tree, but it’s just not the right choice for the way we garden and the climate we garden in. It’s an old-fashioned choice, and we have to look to the future. Mulberries are drought-tolerant, don’t need chill hours, don’t need any kind of spraying, and will feed both wildlife and us. Probably there are other good choices I should be looking into, like guava.

There will be more musings on this subject later, but meanwhile, I’m just happy to have fresh fruit every day to eat first thing in the morning. What a great start to the day!

Oiling Outdoor Furniture

Back in the summer of 2017, Tom asked my father to teach him how to make a farm table for our back patio. They made it together out of redwood, and when it came home, it was beautiful.

The table and benches have been outdoors for two years now, and we use them almost daily - really, every day unless it’s raining. The tables get no protection other than the shade sail that you see in the above picture, and that’s only up in the summer. It gives scant shade, enough to eat or work at the table without getting sunburned. Otherwise, the table is open to the elements. After two years of that, the furniture was looking pretty worn out. The redwood had weathered to a lovely grey, but the wood was dry and unprotected.

Growing up the daughter of a woodworker, I had seen the summer oiling ritual play out every year, but somehow I avoided actually performing this chore myself. We have other outdoor furniture that I have never oiled. Once in a while my dad does it for me, or Tom does it. But really, this is a job I knew I should be handling myself, especially in the summer when I am out of school and am available for projects. So, Adam helped me move the farm table and benches out to the driveway (a surface we don’t care about messing up), and after putting on my ‘painting’ clothes, I armed myself with paintbrush, shop towels, and Penofin, and spent a cool morning working on protecting these priceless pieces of furniture.

Penofin is the product my dad recommends for any piece of furniture that’s going to be outside, especially if it’s in the sun, as it has some UV-blocking attributes. I used the Penofin that is formulated for redwood. It is made from the seeds of the Brazilian rosewood tree. I don’t know how sustainable that is, but the company assures us that no trees are ever cut down to provide the oil.

There are some steps you should take before oiling your furniture. One is to wash the pieces you will be oiling. I did this with a rag and water, the day before oiling. Dad also recommends giving the furniture a light sanding, as the wood will then take the oil better. Apply the oil in a thin layer with a brush, and then let it sit for 20 minutes to soak in. If your wood is really dry, it might need more than one coat (or multiple coats). After oiling and letting it sit for the requisite 20-30 minutes, wipe off the excess with rags or shop towels. CRUCIAL NOTE: whatever you wipe with cannot just be put in the trash can, as oily rags/towels can self-combust. The company recommends soaking them in a bucket of water, which you can do until your trash pick-up day, moving the sodden material to your trash can. The problem then is, what to do with the soaking water? Our street drains go right to our Bay, so I wouldn’t want to put this oily water down that drain. I suppose you could put it in an area of your yard filled with wood chips, but I’m not sure I’d like an oily residue in any area of my yard - especially in flammable CA. Dad uses shop towels (thick blue paper towels you can get at your hardware store) and after they are used for wiping the furniture, lays them out on the driveway to dry until the next trash pick-up. Skipping the wiping step doesn’t work either, as the residue will dry in a tacky layer, and then no one will want to use that furniture.

Dad also recommends applying a layer of epoxy on the bottom face of the feet, to limit any end-grain soaking of water from the resting surface. I did not do this step.

You can really see the difference between oiled and dry furniture, and it really extends the life of your outdoor pieces. You can also see how the used towels are laid out to dry. It looks terrible, but better that than a fire. It might make sense to do your oiling as close to your garbage pick-up as possible.

You also want to make sure to do the oiling a couple of days before a party, as you’ll need time for the wood to fully cure. The brochure says that you can sit on it after 12 hours, but take it from me - a few days is better, and a week is optimal.