Weeds Happen, Part 1

I have to grease our little tractor. That means I have to skootch on my back, grease gun in one hand and manual in the other. I will concentrate on my three hopes:

• That the tractor won’t roll. I know it won’t because it can’t: it’s parked on the level and has both of its appendages (the bucket in front, the brush hog behind) down on the ground, Still, if it rolled just a little roll, I’d be crushed.
• That I can finagle the grease gun to the right angle to couple with the port, and then that I can squeeze the grip (with its man-sized span). And—back to the irrational, that I won’t inadvertently slip and inject grease into my arteries, killing me instantly, which is a “truth” that a big brother used to warn me of.
• That these holes I’m squeezing grease into are actually the right ones. The drawings of circles and lines in the manual are pleasing to the eye and they motivate me to learn how our tractor works, but they don’t’ tell me where the holes are. And I even took the manual back to the dealer once to ask for clarification. His almost helpful clarification: “Put grease everywhere there’s a joint, unless it has a pin. Grease it or lose it.”

In truth, those three hopes are just sub-hopes to our chief one: that we can slow the spread of weeds at our place, in the Oregon Coast Range

Why do we want to slow the weeds? Because many of them have effects or are likely to have effects, that are counter to our plans. Many of these weeds

• Are unpleasant—they have thistles, thorns, tarry goo on leaves or stems, or make needle- and ball-shaped seeds that get stuck all over the dogs.
• Slow or prevent succession toward communities that make more cover.
• Make worse forage or habitat for wildlife than the natives.
• Take space so there is less room for the natives that are serving key physical functions. Natives provide habitat for many of our amphibians, reptiles, mammals, and birds—which belong here, and which we like to have around. Native shrubs along the stream banks help control erosion. Native conifers shade the streams, and then fall into them when they die, slowing the water, and helping the floodplain stay floodplain, rather than becoming a sluice.
• Suck more water out of the ground (because of their higher growth rate). This adds insult to injury for the juvenile salmon, which can’t handle very warm temperatures—and our stream is near their upper threshold. Our riparian restoration goal is to keep more water in the soils so it can seep into streams all summer and help keep temperatures low.

All of the weeds I’m discussing are non-native, and are more technically called “invasive species.” They agonize me the same way accidents do. Deep down, I feel that invasives just shouldn’t have been “let out”—but they were. Like accidents, they “happen.” Globalization—trade, traffic, vacationers—inevitably leads to many species being moved around to places where they outcompete the locals. At such global scales, they can arrive as contaminants of agricultural items like ornamental plants or feed. At more local scales, they arrive on the hooves and fur of wildlife, in the digestive deposits of mammals and birds, in boot and tire treads, with plants we buy, and in bales of hay and loads of gravel. They arrive on the wind.

And like after an accident, we feel obliged to do something to try to put things back. Even though tractor maintenance isn’t second nature to me, as a plant biologist, the job of fighting invasives is. My husband and I know we may not be able to eradicate much of anything, but we also know that reducing their incidence is way better than doing nothing.

~ ~ ~

To fight invasives, it helps to understand what they are. Invasive species are ones that are both introduced (meaning that they are not native to a region), and that can do harm to people, the economy, or the environments around us. Not all non-natives are actually invasive, by that definition. A weed, by contrast, is defined as any plant that is growing in a place where a person doesn’t want it—but a weed can be native, rather than introduced. Most invasives would be called weeds. Here is a list of typical weedy characteristics, most of which are related to growing quickly, taking up resources other plants would use, and producing a lot of seeds that can move around to new places.

• Have a short period between germinating and producing seed.
• Produce many seeds.
• Have abilities for seeds to disperse a long way
• Have seeds that can maintain longevity when buried, have the ability to survive in a variety of habitats and have the plasticity to grow super-well in at least some sites
• Do best in very high-resource environments (high light, high soil moisture, high soil fertility such as found after a disturbance).
• Have strategies that help them get started after a disturbance by growing quickly from plant parts that are left behind, or by sensing that they are closer to the soil surface (by sensing rapid changes in temperature or even light).
• Have strategies that monopolize resources so they get them, and the plants around them do not—broad wide leaves and canopies to shade out the plants nearby, root systems that are great scavengers. Some of them can produce prodigious growth, using biomechanical tricks that work for the short-term of their lives (they need to reproduce in a short period so that they are insured to get some seed, even in a bad year)—hollow stems that let the plant be tall and strong without much investment in support.

I’ve listed the non-natives at our place. This list doesn’t count the species we planted on purpose, like apple trees, and it only includes one grass because we haven’t identified the grasses yet. The way I categorize species is really just my opinion. As the definition of weeds implies, weediness is in the eye of the beholder. Biology plays a role, too, because how bothersome a species is at a particular place depends on all sorts of factors, like climate, soils, pests, and what else is growing there.

The first list is the invasive non-natives that we really wish were not here. This list is 25 species, which represents almost 10% of the naturally-occurring (native or non-native, not planted by humans) flowering plants at our property.

Invasive non-natives we try hard to control (8 species)
black knapweed	Centaurea nigra
Canada thistle	Cirsium arvense
herb Robert	Geranium robertianum
St. John’s-wort	Hypericum perforatum
reed canarygrass	Phalaris arundinacea
Himalayan blackberry	Rubus bifrons
evergreen blackberry	Rubus laciniatus
tansy ragwort	Senecio jacobaea
Invasive non-natives we try less hard to control (3 species)
field bindweed	Convolvulus arvensis
teasel	Dipsacus fullonum
European bittersweet	Solanum dulcamara
Invasive non-natives we don’t try to control—seems like a lost cause (14 species)
hedge bindweed	Calystegia sepium
queen Anne’s lace	Daucus carota
lapsana	Lapsana communis
oxeye daisy	Leucanthemum vulgare
birdsfoot trefoil	Lotus corniculatus
peppermint	Mentha piperita
wall lettuce	Mycelis muralis
smartweed	Persicaria hydropiper
English plantain	Plantago lanceolata
broad-leaved plantain	Plantago major
creeping buttercup	Ranunculus repens
curly dock	Rumex crispus
bitter dock	Rumex obtusifolius
tall sock-destroyer	Torilis arvensis

The next set is invasive non-natives that are either less threatening than those on the previous list. These 20 species may stop being problematic when we decrease the extent of their habitat, or they are simple to control and don’t spread very quickly at our place.

Invasive non-natives we mostly watch and see (20 species)
Powell’s amaranth	Amaranthus powelii
scarlet pimpernel	Anagallis arvensis
common burdock	Arctium minus
leafy beggarticks	Bidens frondosa
three-leaved beggarticks	Bidens tripartita
goosefoot	Chenopodium album
bull thistle	Cirsium vulgare
toothed coast burnweed	Erechtites minima
petty spurge	Euphorbia peplus
hairy hawkbit	Leontodon saxatilis
whitetop	Lepidium appelianum
pennyroyal	Mentha pulegium
yellow parentucellia	Parentucellia viscosa
wild basil	Satureja vulgaris
woodland groundsel	Senecio sylvatica
black nightshade	Solanum nigrum
spring sowthistle	Sonchus asper
annual sowthistle	Sonchus oleraceus
sandspurry	Spergularia rubra
dandelion	Taraxacum officinale

The last set is the 38 non-natives that are more or less all right with us. In some situations, they would be considered mildly to severely invasive.

Non-natives that we mostly let be (38 species)
stinking chamomile	Anthemis cotula
atriplex	Atriplex
English daisy	Bellis perennis
common centaury	Centaurium erythraea
big chickweed	Cerastium fontanum
sticky chickweed	Cerastium glomeratum
smooth hawksbeard	Crepis capillaris
Deptford pink	Dianthus armeria
foxglove	Digitalis purpurea
wall bedstraw	Galium parisiense var leucarpum
cut-leaf geranium	Geranium dissectum
dovefoot geranium	Geranium molle
marsh cudweed	Gnaphalium uliginosum
spotted catsear	Hypochaeris radicata
sharp-leaved fluellin	Kickxia elatine
prickly lettuce	Lactuca serriola
red deadnettle	Lamium purpureum
small forget-me-not	Myosotis discolor
common forget-me-not	Myosotis scorpiodes
prostrate knotweed	Polygonum aviculare
self-heal	Prunella vulgaris
common plum	Prunus domesticus
field mustard	Rapa campestris
sweetbrier	Rosa eglanteria
sheep sorrel	Rumex acetosella
western pearlwort	Sagina decumbens subsp. occ.
field madder	Sherardia arvensis
common chickweed	Stellaria media
bur clover	Trifolium dubium
red clover	Trifolium pratense
white clover	Trifolium repens
flannel mullein	Verbascum thapsus
small speedwell	Veronica arvensis
thyme-leaved speedwell	Veronica serpyllifolia
tiny vetch	Vicia hirsuta
smooth tare	Vicia tetrasperma

Altogether, we have 83 non-native species at our property. That means that about 28% of the types of plants are ones that came from somewhere else—and that is a lot. The quest to eradicate keeps us busy out there, but I must say, it also takes us to corners of the property at times of the day and seasons when we otherwise wouldn’t be out there. And some of these non-natives are downright pretty.

My next post has the methods we use to control some of these species. We use the whole gamut, from stomping to hand-pulling to snipping the flower heads off, to spraying with herbicides, and all the way to mowing with the weed-eater or the tractor.

Which brings me back to the tractor maintenance—to my worries about it rolling over me, and about how to get grease into the proper little holes and not into my arteries. And that will make me think of brothers, and fathers, and then of my children. Generations, past and future. That will make me think of trees that grow, streams that flow, fish that mature and swim to the ocean, and come back again.

I’ve got to grease that tractor. Grease it or lose it.