Weeding Earlier Rather Than Later


Weeding is not much fun. Some of us might enjoy the relaxing monotony of productive weeding. Realistically though, most of us would prefer to do something else in the garden. There is certainly plenty of other chores that need to be done now, after earlier rain, and before the weather gets significantly warmer. However, such weather is why it is important to start weeding earlier than later.

By definition, weeds are weeds, because they are unwanted. They get to be unwanted by dominating space and exploiting resources more aggressively than wanted plants. Some innately grow faster and more aggressively than most other plants. Some are innately prolific with seed. Some employ multiple tactics to gain unfair advantages. Weeding is how we help our gardens compete.

Weeds grow throughout the year. Most slow down through the dry warmth of summer, and many die off then. However, there are always some weeds growing somewhere. When they die off, it is only after they have dispersed seed for their next generation. Some generate a few generation annually. Some are perennial weeds, or even shrubs, vines and trees, which survive for many years.

Weeding is more of a concern now because the majority of weeds grow so much more aggressively after the earliest rain of winter. Warming weather later in winter accelerates their proliferation. This is the time of year that weeds start to crowd desirable plants. If weeding is delayed for too long, weeds eventually bloom and toss seed. Some weeds extend stolons to disperse vegetatively.

The good news is that the same rain that promotes the proliferation of weeds also facilitates weeding. Weeds are easier to pull while the soil is still damp than they will be as the soil dries later in spring and summer. Also, while weeds are still fresh and turgid, they are less likely to leave roots or stolons behind in the soil. They are more difficult to pull intact as they begin to deteriorate later.

Furthermore, weeding should be done before weeds bloom and disperse seed for subsequent generations. Some are sneaky and quick.

Wild Strawberry?

Wild strawberries are worth salvaging.

Under a bank of carpet roses that I am none too keen on, this grubby ground cover competes with more aggressive weeds. To me, it looks like common mock strawberry, Potentilla indica. I never gave it much though. It seemed to me that whoever had installed cheap and common carpet roses on that bank would have employed a comparably cheap and common ground cover.

The ground cover was more prolific in open spots that were too narrow for more of the roses, and from there, seemed to have migrated under the roses as a second layer of ground cover. It would not have been installed underneath intentionally. It did not occur to me that it may have grown from seed like so many other weeds there, or migrated in from the surrounding forest.

The white flowers did catch my attention though. I was not aware of a mock strawberry that bloomed with white flowers. I really was not concerned enough about it to investigate. This part of the landscape will be getting renovated soon anyway. The roses will be relocated to where they can not extend their thorny canes into an adjacent walkway. Agapanthus will replace them.

Now that I am seeing more of these odd strawberries, I am wondering if this low ground cover that I formerly had no regard for is actually the native wild strawberry, Fragaria californica. Not only should mock strawberry bloom with yellow flowers, but it should also produce more spherical berries. Now I will need to identify it before I either dispose of it, or merely relocate it.

I prefer to not salvage exotic species that exhibit potential to naturalize from landscaped areas into surrounding forests. If this ground cover is wild strawberry, it migrated from surrounding forests into a particular casually landscaped area.

Poison Oak Tree

P91229From below, this looks like a shrubby deciduous tree. It is really just a Douglas fir, like those around it. All the defoliated thicket growth is overgrown poison oak. It has likely been climbing the fir tree since it was quite young. Poison oak is not very proficient at climbing bare trunks. It typically climbs into lower limbs, and then into higher limbs before the lower limbs are shed.

No one has bothered to cut this poison oak out of the fir tree because it is not within a landscapes area. That dark margin at the top of the picture is the underside of a bridge, from which, not much of the thicket growth below is visible. The area from which this picture was taken is used for piling greenwaste and parking, where no one is concerned about wild vegetation beyond.

However, now that I sometimes park in that particular parking area, I am finding this mess of poison oak difficult to ignore. There was a similar but even bigger thicket of poison oak up in a redwood tree at the farm, from where it tossed seed into horticultural commodities below. The resulting seedlings added a whole new dimension to weeding the stock. The thicket had to go.

The problem with the thicket in the picture above, although not as serious, is that it too tosses seed into area where people work. Seedlings are likely to grow where greenwaste is processed, and where I sometimes park. Poison oak that grows on the far side of this fir grove will be uncomfortably close to the right field foul line of a ball field that will eventually be restored there.

I have no intention of cutting the poison out of the fir tree. I will merely sever the main trunk at the base, as seen in the picture below. As it deteriorates over several years, no one will mind if it is somewhat unsightly on the industrial yard side. The adjacent fir trees sufficiently obscure it from view from the ball field side. The priority will be preventing seed from proliferating.P91229+

Snails, Weeds And Falling Leaves

P90713KThe coloring of foliage is a bit slow this autumn. The cooling nights after such warm weather is bringing some of the deciduous foliage down while it is barely yellowing. Honeylocust and black oak have already gotten notably sparse without much notable color. Hopefully, the more colorful sweetgum, flowering pear, pistache and gingko trees will retain their foliage later into cooler weather, so that they can put on a worthy show before filling compost piles.

It is probably slightly too early to clean gutters and downspouts. Unless the rainy season somehow starts first, this should probably wait until most of the foliage that is expected to fall has already fallen. Lawns, certain ground covers, decks and pavement should be raked as needed though. Decks and pavement can get stained from the tannins that leach from decomposing foliage. Lawn and ground cover do not like the shade under the debris.

However, slugs and snails really dig the mess. Fallen foliage keeps the ground cool, damp and shaded. Raking leaves does not eliminate slugs and snails, but inhibits their proliferation. There are always plenty of other hiding places. As the weather eventually gets cooler and damp, snails that stay out in the early morning should be collected and disposed of. Of course this technique is not convenient for everyone, since most snails hide before the sun comes up. Small slugs hide earlier in the morning and are even more unpleasant to handle.

Once found, neither slugs nor snails are too elusive . . . or fast. Yet, plucking and collecting them is not a fun job. Once collected, no one knows what to do with them. They can be put into plastic bags and disposed of; and will eventually succumb. Some people prefer to simply toss them onto a dry and sunny driveway or roof where they succumb more quickly and get taken by birds. Snails may need to be squashed to limit mobility.

Even though it is too late to prevent most types of weeds from dispersing their seed, a few types continue to disperse seed as they deteriorate through autumn and winter. Weeds in areas that get watered last longer and disperse their seed later than those without watering. Perennial weeds that are still green in dry areas areas will be easier to pull after the first rain.

Cortaderia jubata

P90908It is known by a few different common names, including ‘Andean pampas grass’, ‘purple pampas grass’, and simply ‘pampas grass’. ‘Andean pampas grass’ sounds almost like an oxymoron, since the Andes Mountains are in a separate region to the west of the pampas region of Uruguay and eastern Argentina. ‘Purple pampas grass’ is even sillier, since it is devoid of any purple.

I know it simply as ‘papas grass’. That is just how I learned it. The problem with this common name is that it is the same common name of Cortaderia selloana and its cultivars, which is a distinct species that is, on rare occasion, planted intentionally in landscapes. Cortaderia jubata is one of the most aggressively invasive of exotic species on the West Coast, so is not planted.P90908+

Cortaderia selloana is safe to plant because it is ‘supposedly’ sterile, so can not naturalize. Technically though, it is not really sterile, but merely exclusively female, without male flower parts for pollination. It reproduces by apomixis, which is a fancy way of saying that it produces viable seed without pollination. No one has bothered to explain why that makes it any less invasive.

Cortaderia jubata reproduces by apomixis too, but makes much more of problem with it. It is very prolific with its unpollinated seed! To make matters worse, it will hybridize freely with Cortaderia selloana if it gets the chance. How does that even work?! Pollen is needed for that sort of hanky panky! Nonetheless, the hybrids are almost as aggressive as Cortadera jubata is!P90908++

I just don’t trust any of them. Cortaderia selloana cultivars can work well in large landscapes in urban areas, where they can not escape into the wild. For rural or suburban landscapes that are near wildlands, there are plenty of other less invasive options.P90908+++

Bad Picture Of Good Berries

B90803KHimalayan blackberry is to cane berries what blue gum is to eucalypti. It is what gives all cane berries a bad reputation, and is why so few of us want to grow them. Himalayan blackberry grows as an extremely vigorous weeds, extending sharply thorny canes over anything within reach. When the canes are removed, the tough roots are extremely difficult to remove and kill.

If ignored, the canes ‘leap’, which means that they develop roots where they arch back downward to touch the ground. From there, they grow into new plants that extend new canes in all directions, to start the process all over again. (‘Leaping’ is like ‘layering’, which involves the development of roots where stems ‘lay’ on the ground.) Their seed gets where their canes do not.

The thorns are ‘prickles’, which really is a technical term for sharply pointed distensions of bark or epidermis. They are more like stout prickles of rose canes than the more finely textured prickles of garden varieties of cane berries. They are rigid, extremely sharp, and curved inward to snag victims on their way out; so are seriously wicked and potentially dangerous to handle.

Harvesting berries from second year canes is not easy. Most are out of reach within bramble thickets. Because they ripen through a long season, they must be harvested repeatedly, as those that were unripe during a previous harvest finish. This is why there are black, red and green berries in the same picture. The berries are small and variable, with good years and bad years.

This happens to be a good year. The thorny truss of a few small berries in the picture may not look like much; but there are plenty of them. The berries are quite richly flavored too. Those who have the patience to collect them will get some good jam or jelly out of the deal.

Perennial Pea

90710Whether it is grown intentionally, or considered to be a common roadside weed, there is no denying that perennial pea, Lathyrus latifolius, knows how to brighten some of the wilder parts of the garden with brilliant purplish pink bloom. Some garden varieties bloom either pale pink or white, just like a few random feral plants do. Bloom resembles that of sweet pea, but without fragrance.

By their second year, the potentially six foot long vines might be a bit too rampant for more refined situations. They happen to work nicely to climb over wood piles and otherwise unsightly chain link fences though, even if only temporarily until they die back to their fat subterranean taproots by the end of summer. They will be gone before the firewood they conceal becomes useful again.

New bluish green growth regenerates vigorously at the end of winter, but does not bloom until early summer. The compound leaves are comprised of only a single pair of narrowly oblong leaflets with a branched tendril in between. Each leaflet is about two inches long and less than half as wide. Stems and petioles are winged. Once established, perennial pea can be difficult to eradicate.

Weeds Might Produce Hazardous Seeds

90710thumbWeeds are weeds because they grow where they are not wanted. They might be desirable plants in the wild within their native ranges, or beyond their native ranges where they are useful, but for one reason or another, are undesirable in other situations. In fact, many of the most invasive exotic (non-native) weeds were imported because they were useful for something, and then escaped.

Many invasive exotic weeds that were not imported intentionally by humans likely stowed away intentionally by their own means. Some produce edible fruits that contain their seed so that animals who eat the fruit transport and disperse the seed. When animals such as cattle, swine, sheep, horses and chickens are imported, they can bring such seeds with them, and have already done so.

Not all plants have such mutually beneficial relationships with the animal vectors who transport their seed for them. Rather than expend resources on fruit to appeal to, and reward the animals who eat it, they produce seed structures that cling to animals. Most get tangled in the hair of mammals. Some get wedged into cloven hooves. A few are just sticky enough to stick to the feet of birds.

It is sneaky and exploitative, but effective. Most of these sorts of seed structures stick to the fur only for short distances before falling to the ground, where they really want to be. Some types cling for longer distances, in order to take advantages of larger migratory mammals. Dispersion is their objective. Even though they provide no benefit to their vectors, they do not intend to harm them.

However, they sometimes do. Sharply pointed seed structures that are designed to slip smoothly into fur, but not come out easily, can get into eyes, noses, ears and throats of innocent animals. Foxtails are the most dangerous, and sometimes need to be removed by a veterinarian. Burclovers get tangled in soft fur, and sometimes do so in very uncomfortable clusters.

Domestic dogs and cats are more susceptible to the dangers of weed seeds than wild animals are, because their fur is longer, shaggier, and maybe curlier.

Six on Saturday: Sedge Removal


What a nasty job! We know this sedge, or whatever it is, as ‘razor grass’ because it cuts like razors. It is difficult to pull from the rocky creek bottom and bank with the creeping stolons still attached. The creek is mucky. The water is wet. The gloves I wear to avoid getting slashed obviously get just as mucky and wet.

It was such a miserable job last autumn that we postponed most of it for winter. I figured that I could wait for the dangerous foliage to die back, and then just pull up the stolons below the dead foliage. It might have been a good idea, if only we had returned to actually execute our plan. By the time we got back, new foliage was already maturing.

I was so dreading returning to this job, but then found that the fresh new foliage was not nearly as dangerous as the more mature foliage that we pulled late last summer and autumn Furthermore, the new rosettes had not dispersed their roots quite as firmly as expected. They were suspiciously easy to pull, with the stolons still attached. Dead old rosettes seemed to be completely necrotic and decayed. It was too easy.

I expect at least a few new rosettes will develop later. There were likely some down under the muck that were not up when I was there. I also expect that some will grow from bits of stolon that were left behind. However, nothing has been seen in the past three weeks or so since we did this. (I would have shared these pictures sooner, but there were other pictures to share instead.)

Speaking of other pictures to share, there are six more on my secondary ‘Six on Saturday‘ post. I did not want to save them for later because they are almost irrelevant to horticulture, but I did not want to delete them without first sharing either.

1. Sedge, or whatever it is, is difficult to handle, and is even more difficult to handle when trying to separate the stolons from the stones on the bank of the creek.P90629

2. It did not take long to fill each of these plastic bins. I did not leave any foliage hanging over the edge, because I did not want to get cut when picking up the bins.P90629+

3. These bins can be used as a flotation device. Actually, it was rather annoying that they kept floating away until they got filled. It was a nice day to be in the creek.P90629++

4. This acorus grass was mostly overwhelmed by the sedge, or whatever it is. I should have gotten a ‘before’ picture. It looks great now, and is happy in the muck.P90629+++

5. While pulling sedge, I found these two knees developing from the roots of one of our two bald cypress. This particular tree was supposed to be a dawn redwood.P90629++++

6. I also noticed that the montbretia was blooming more than it normally does down in the deep shade. It is a voracious weed too, but inhibits even worse weeds.P90629+++++

This is the link for Six on Saturday, for anyone else who would like to participate:


Like Peas In A Pod

P90622KGenerally, that is how they are. Almost all perennial pea flowers bloom with the same bright purplish pink color of the bloom in the picture below. That is, of course, before their pods develop, but you get the point. We sort of know what to expect from them.

As I mentioned in the ‘Six on Saturday‘ post last week, from which the picture below originated, variants like the pink bloom in the picture above are sometimes observed. The rare clear white flowers are my favorites. There might be fluffier double flowers too; although, in my opinion, the single flowers are prettier and look more like pea flowers should look.

I also mentioned last week that, although perennial pea has a sneaky way of growing where it is not wanted, it typically does not grow reliably from seed sown intentionally where it might actually be desirable. I have tried. The seed just did not cooperate. I managed to get a few to grow, but only because I put out a few hundred to compensate for the expected minimal rate of germination.

Because I like the white so much, I took seed from a vine that had bloomed with single white flowers. I figured that they would be more likely to produce a few white blooming progeny. I would have been satisfied if only a single vine in a group of several bloomed white, but got only a few vines that all bloomed with the typical bright purplish pink. They were pretty nonetheless, but were ironically removed when the site was redeveloped.

I also collected seed from vines that bloomed with the common single bright purplish pink flowers, just in case the viability rate of their seed might somehow be better. They were sown into a different situation, so even if I happened to know how many of the seed that were sown germinated and grew, it would not be an accurate comparison. Regardless, I was no more impressed with the result. Perennial pea is best appreciated as weed.P90615+++++