Bella Vista Park, Oakland, California
A Landscape Analysis done from Winter 209 to Spring 2010
The goal of this report is to establish a record for future generations of the condition of the park in the spring of 2010. The observations noted here were done by Jerry Heverly, 2510 Eleventh Avenue, Oakland, California between the fall of 2009 and April of 2010.
My qualifications for this report involve my tenure as an instructor of horticulture at Diablo Valley College, Pleasant Hill, California and Merritt College, Oakland, California in the 1980’s. During that time I primarily taught Arboriculture, Soil Science and—most relevantly to this enterprise—Landscape Maintenance. It was in the latter course that I taught professional and amateur gardeners how to analyze landscapes, their problems and the economic consequences of those problems.
During the time when Bella Vista Park was being renovated in the early part of the 21st century I served on the neighborhood committee that worked with the city and the non-profit agency that governed the changes to the park that are now well established and will be the subject of this report. I was privy to many of the decisions that ultimately became the park landscape. However, due to a conflict with one member of the committee I left that organization a few years ago. I have maintained email contact with the committee and have been able to keep some kind of awareness of recent developments. I’m sure, though, that some of the suggestions incorporated within this report may not be feasible due to budgetary constraints and other factors unknown to me.
My report was done by walking the park with a few basic tools including a ruler, a magnifying glass and pruning shears. I began nearest my home in the narrow strip along Eleventh Avenue. I then proceeded into the park walking clockwise to the gate on Tenth Avenue. I then walked the strip along Tenth Avenue. I did not concern myself with the grounds of Bella Vista School, which was not part of the park renovation. I did two thorough walkthroughs, one in the fall, and one in April. I supplemented these visits with shorter walks throughout the winter. I tried as best I could to quantify any observations I made in order to give later observers something to measure against. Thus I used diameter-at-breast-height measurements to indicate the health of trees, though I also tried to include some subjective comments to add to the detail of the report.
Any recommendations that I have made in this document I highlighted in red.
Eleventh Avenue strip:
There were four Tristania conferta(Brisbane Box) trees and three Quercus suber (Cork Oak) trees here. All were healthy and showing signs of rapid growth, however the Tristania across from 2614 Eleventh Avenue had numerous basal suckers that had been cut back one or more times. (I cut a few off myself this spring.) It’s clear that if this cutting is not done annually for the next five to ten years this tree will turn into a large shrub.
The dbh’s of the Tristania’s were, 6.6 cm.; 8.2 cm.; 7.8 cm.; 7 cm.
The dbh’s of the Oaks were, 12.9 cm.; 13 cm.; 11.4 cm.
It should also be noted that the local squirrels have buried enough acorns to produce several oak seedlings in this area. I’m guessing they are Quercus suber but it should be noted that there is a Quercus ilex directly across the street that might be the source of the seedlings. It would probably be wise for someone to periodically cut down these seedlings so as not to produce an overly dense oak forest here.
The original idea for this strip was to have an inexpensive, easy to maintain patch of plants tolerant to the wet conditions here. My recollection is that everything that was intentionally propagated here was done via seed. Below you will see that very little of the original planted material remains.
The wetness of this strip comes, I think, from two sources: one, there are several drains that take water from the park above and run it through this area. And two, this area, was before it was developed, a streambed or at least an area where water typically ran off during the rainy season. This natural drainage also accounts for the alluvial, sandy loam soil in most of the park as opposed to the clay soils evident in other parts of Oakland.
The Soil Survey of Alameda County, done in April 1975, lists this area as Urban Land—Tierra Complex-15 to 30 percent slopes. The report says, in part: “This complex is about 50 percent Urban land, 25 percent Tierra loam, and 20 percent Azule clay loam. Included in mapping and making up about 5 percent of the complex are small areas of Los Osos silty clay loam.” After I write up this report I hope to do some soil sampling to be added as an addendum in May.
Wherever I have been able to dig into the soil of the park I have found sandy loam soils. I’d also note that the soil in my own yard, which is very close to the park, is a sandy loam. It is possible, however, that there are pockets of clay in the park.
Because this area was intended for very little human maintenance there have been significant changes in the plant material over the past few years. As far as I can tell only one species, a clumping ornamental grass, survived the first few years of relative neglect. I have observed that periodically (twice a year?) the city gardeners mow down all the non-tree vegetation here with weedeaters. That means that only plants that can survive this kind of treatment are still around. The ornamental grass is tough and, like most grasses, has its meristematic tissues protected just beneath the surface of the soil. Any shrubs or perennials that were seeded in probably succumbed to the weedeater in the first year or two after renovation.
What now fills this space is an assortment of Eurasian weeds common to any vacant lot in the Bay Area. Some of these weeds might be deemed desirable or at least tolerable. I’ve tried to give my opinion about some of these invaders below.
There are about a dozen broadleaf weeds evident in this strip.
Down at the western end of the strip (opposite 2610 Eleventh Avenue) I found large numbers of Malva—Cheeseweed (in general I’ll stick to genera in my descriptions because I often don’t know the species). This is where the most water accumulates and the Malva’s thrive here. There is also Sonchus—Sow Thistle; Senecio vulgaris—Common Groundsel; Bromus—Brooms; one or two Amsinckia—Fiddleneck; some Avena—Wild Oats; and, in a few open areas, Anagallus—Scarlet Pimpernel. This is the area where the weeds are the tallest and the most crowded. Various grassy weeds predominate.
The one plant worth special mention here is Trifolium—Clover. Is this a weed? I suspect it was a minor part of the seed mix that was originally sowed here. Clover, because it can fix its own nitrogen, thrives in Oakland in places where there has been little or no fertilization. Northern California soils are very deficient in nitrogen (at least if you want to grow non-native plants). Anything that can deal with this deficiency—which includes most plants of the Clover Family—will out-compete other genera. My own bias is that the stewards of the park should try to foster this clover growth, at least in spots like this. Trifolium will reduce erosion and have other beneficial effects on the landscape. Trying to eradicate it would be very difficult. If I were to pick one ‘winner’ for this strip it would be the clover.
Note added in late April. I’ve been doing some weeding in this area and have uncovered many ornamental grasses from the original planting. I have a suggestion. Why not see into this area some aggressive native perennials that might crowd out the Eurasian weeds? What about California poppies or Monkey Flower (Mimulus californica)? Seed is cheap. This should be done in the fall when the rains could help the seedlings along
Opposite 2614 Eleventh Avenue I found one Picrus echioides—Bristly Oxtongue.
This is the first place I encountered a solid mass of Cynodon dactylon—Bermudagrass. This presents a big problem for the park. Bermuda grass has taken over about 40% of this strip right now. My experience tells me that in five years this plant will occupy 90% of the strip landscape unless something is done about it soon. I don’t know the politics of this situation so I will just offer some options.
Is it legal to use herbicides in the park? Would the nearby residents acquiesce in herbicide use? I don’t know. But there are several hebicides that could selectively remove the Bermudagrass without harming the co-mingled species. In my view they are safe and sensible.
If herbicides are not used the entire park will someday be one big Bermudagrass plantation. At the eastern end of this strip the Bermudagrass is thick and thriving. Because there is a short wall between the strip and the lawn inside the park there has not yet been any Bermudagrass incursion into the park. But my experience tells me that it is only a matter of time before the Cynodon gets a foothold inside the park. Once that happens it will be about three to five years before the park lawn will gradually convert from the present species (tall fescue and clover) to Bermuda. Within ten years Bermuda will cover all the groundcover areas in the southwest corner of the park.
Opposite 2622 are two other species. Someone planted a line of low shrubs, Phygelia, that are thriving. But just to the east of these shrubs is a thick stand of Plantago lanceolata—Plantain. Why these are so dense here I don’t know. I’ve never seen a stand of this particular weed that had so taken over a spot like these have. Plantain is very difficult to dig up. The roots go down a long way. There are several herbicides that would kill them off quickly, but, as stated above, I don’t know the politics of this.
As you walk east opposite 2632 & 2700 you find a thick growth of Bermudagrass plus a few common broadleafs: Anagallus, Wild Oats, Sonchus and two large, nasty thistles. The thistles are among the most unpleasant weeds you can have in a place like this, covered with painful thornlike growths. These could be dug up and removed, but wear gloves. {Note: I removed most of the thistles.}
The final area before you reach the park gate has two important problems: one, there is a small stand of Oxalis just starting along the wall. Oxalis is so troublesome bccause it has two frustrating ways to propagate itself. If you disturb the yellow flowers it shoots tiny seeds out of the flower. If you try to dig it up the plant has tiny tubers in the soil that are almost impossible to remove completely. But I strongly recommend that someone immediately try to dig these plants up before they reproduce as they have on the Tenth Avenue side. More about that later.
The second big problem is the Hedera canariensis—Algerian Ivy, that is growing here. This plant, if left alone, will spread and choke out everything in its path (except Bermuda grass which can survive underneath the ivy). Since there is lots of Algerian Ivy in the southeastern corner of the park this weed will always be a problem. But it is possible to hold it back if someone is willing to dig it up now before it’s too late.
I should note the huge Quercus rubra—Red Oak, at the park entrance. There are, of course, several surrounding the school that apparently date back to the building of Bella Vista Elementary. Ten to fifteen years ago some ‘gardeners’ from the school district began to butcher several of these oaks. They began with the one at the southeast corner (28th and Eleventh Avenue). That tree was brutalized before a concerned neighbor called to complain, halting the massacre. All the trees recovered. The one here at the park entrance escaped the onslaught entirely. It is at least 70 feet tall. I noticed no insect damage or evidence of disease in this tree.
Beyond the entrance is a small weed patch with an assortment of spring annual weeds right now including Sonchus, Wild Oats, a couple Dandelions, a low-growing grass that is probably Paspalum—Dallisgrass, and lots of Picrus. More importantly Algerian Ivy will soon take over the whole patch. This land belongs to the school district so it’s only relevance to my report is that it will act as a nursery for Algerian Ivy, which will eventually move in force to other parts of the park.
Here’s a record, from my notes, of the major weeds along Eleventh Avenue. I put this here for the benefit of that person in 2030 who might want to compare the park landscape to the way it was twenty years before:
I noted the following weeds opposite 2610:
Malva (cheese weed); Senecio vulgaris (Common groundsel); Bromus rigidus (Ripgut brome); Amsinckia intermedia (Fiddleneck); Avena fatua (Wild oats); Taraxacum officinale (Dandelion); & Anagallus arvensis (Scarlet Pimpernel).
All of these are pretty standard spring and perennial weeds of vacant lots.
2614: Picrus echioides (Bristly Oxtongue); Conyza bonariensis (Fleabane); and Cynodon dactylon (Bermuda grass) are here. My notes say there is a seedling of red oak that should be dug up before it gets too big.
2622: Plantago lanceolata (the same Plantain that is so abundant on the 11th Avenue side) is here. Same for 2626.
2632: More weeds noted: Anagallus, Avena, Cynodon and Sonchus.
2700: There’s a big thistle (ouch) here but the main thing is that Bermuda grass is taking over everything and will eventually crowd out everything else except the Algerian Ivy.
2706: Oxalis pes-caprae (Oxalis) is the biggie here. I notice someone handweeded the Oxalis recently but that will do little good. This weed has tiny bulblets in the soil that will regrow quickly. If herbicides can’t be used that someone will need to hand weed this Oxalis three to five times each year to keep it in check.
Inside, Eleventh Avenue side:
One of the most surprising parts of the park is the lawn to the left of the entrance. Typically after about two years a lawn like this would be taken over by weed grasses, primarily Poa annua—Annual Bluegrass, along with dandelions and assorted broadleaf weeds. Usually the city gardeners carry seeds of these weeds on the blades of their mowers.
For reasons I can’t fathom this has not happened at Bella Vista. Instead the lawn actually looks healthy and thick. I found very little evidence of Poa. There is a small patch of it just beginning at the extreme southeast corner of the lawn but I couldn’t find any elsewhere. What I did find was that clover had inserted itself in just about every open space in the lawn—which I consider a good thing. The result of this invasion is that the grass is thick and green; thick enough to provide a nice surface for picnickers or kids who want to roll around. Whatever bare spots have cropped up over the past few years have been filled by this clover. By quantity I found the lawn to be about 60% clover; 30% Alta Fescue—tall fescue, the grass that was originally sodded in—plus a handful of weeds: Bellis perennis—English Daisy; Taraxacum—Dandelions; and Lolium—Annual Ryegrass.
I want to emphasize that this is one of the best lawns I’ve seen in a park in Oakland in my life. I can only guess that the city gardeners have been regularly fertilizing this turf since it was put in, which might account for why it is so thick and green. And the sprinkler system must be working reasonably well, otherwise there would surely be large areas of Annual Bluegrass. This is a big, and unusual, asset for the park.
The trees planted in the lawn are Pyrus calleryana—Ornamental Pear. I think it was a terrible mistake to plant these trees in the park. The reason I say so is a disease called Fireblight. Fireblight is a fatal bacterial disease which attacks certain plants in the rose family like pear trees. I can testify that this disease if rampant in this neighborhood. I’ve lost several trees to this bacteria. Several street trees on Eleventh Avenue died from Fireblight in recent years. (Alas, those dead trees were replaced with more pear trees.)
At this point in early spring I can’t tell whether there is any fireblight in the trees inside the park. I thought I saw some evidence of the disease (in only one tree) last fall but when I did my spring walk I couldn’t see any. But this disease enters through flowers (the trees have just begun flowering this month) and spreads very rapidly downward from the flowers into the branches of the tree, and eventually into the central trunk of the tree. It is very difficult to stop it once it gets started. I will watch these trees over the next three weeks to see if they are infected.
The dbh’s of these pear trees are, 10 cm.; 7.7 cm.; 8.3 cm.; 7.5 cm.; 6.4 cm.; 8.2 cm.
The trees look very healthy. They have obviously grown rapidly since planting. If they can avoid the Fireblight organism they will make good park trees. However, based upon my experience of the neighborhood I would expect these trees to succumb to Fireblight within three years. Cutting these trees down now, at their present robust size, would be heartbreaking, but I full expect that that is what is ahead. It might even make sense now to plant two or three seedlings of another species (which could be purchased cheaply since they wouldn’t need to be large) so that, when the pears are cut down there will be replacement trees already started.
The Native Garden:
I found the native garden surprisingly undamaged by children. I expected to see many broken and trampled plants but I found almost none of this. The Butterfly bushes look healthy and, if anything, a bit over grown. The ground had a few broadleaf weeds but nothing terrible. In the southeast corner of the garden clover had begun to assert itself as a ground cover. As stated above, I think clover is an asset and should be allowed to gradually cover the bare soil in this part of the park.
I would note a few things that might be useful to know:
• There is some Algerian Ivy in the southwest corner that needs to come out ASAP.
• There is a healthy crabapple tree in the garden with a dbh of 4.5 cm. (I should note that crabapples are more susceptible to Fireblight than Pyrus calleryana, so I would expect this tree to die within three years.
• There is a large Baccharis pilularis—Coyote Bush, in the garden. It’s a native but it also is very invasive. I would expect there to be dozens of little Coyote Bushes next spring. Those should be dug up and removed as necessary.
• The citrus tree next to the fence has dozens of basal suckers. They have been cut back repeatedly and that will probably be necessary for as long as the tree is there. Also, the tree is showing extreme symptoms of ‘Lime-Induced Chlorosis’ because the pH at that spot is about 6.9 while citrus would like it about one point lower. I would recommend you invest in a 50 pound bag of granular sulfur. This would be sprinkled on the ground near the tree two to three times per year.
• There is also a Pyracantha bush in the garden, a non-native. This, also, is highly susceptible to Fireblight. It’s also very thorny. Why not get rid of it?
The stage and Adjoining areas:
The trees in this area, primarily Sequoia sempervirens—Redwoods, seem to be thriving. The ground has been kept bare with some old mulch remaining. I saw very few weeds.
Redwood dbh’s beginning at the stage and going north:
13.5 cm.; 11.8 cm.; 9.8 cm.; 8 cm.; 8.2 cm.;
Then over nearer to Tenth Avenue side:
12.4 cm.; 10.1 cm.
There are a few pear trees near the stage:
Dbh’s 7.6 cm.; 9.5 cm. (Because of a condition called allelopathy trees grow faster in bare areas then they do in grassy areas, hence these pears are fatter than the ones in the lawn.
I did note a few broken sprinklers in this area. This actually might be a good thing! Redwoods are natives and generally should not be watered in the dry season or at least very infrequently. The broken sprinkers are probably preventing the overwatering of these trees.
There were some Festuca alta—Ornamental fescue grasses, planted in this area. My notes say they are ‘barely surviving the foot traffic’.
If you ever have the money it would be great to add mulch to these areas.
This areas apparently was populated with many low-growing shrubs. Many seem to have disappeared. The remaining plants, Ceanothus—California Lilacs, are looking sad. I wouldn’t expect them to survive much longer owing to frequent trampling by little feet.
There are three Brisbane Boxes here:
Dbh’s 5.7 cm.; 6.5 cm.; 6.5 cm.
Then there are more Redwoods in the northwest corner:
Dbh’s of Redwoods 6.3 cm.; 8 cm.; 7 cm.; 6.8 cm.; 5.7 cm.
These latter Redwoods show salt damage. My guess is that someone, in an effort to save the Ceanothus shrubs in this area, fertilized this section, probably more than once. Redwoods should not be fertilized. (Actually no trees should be fertilized.) This salt damage has slowed the growth of these trees (note the smaller dbh’s on these compared to those near the stage.) The rains we had this winter probably washed out any left over salts from previous years. I strongly recommend that you talk to the gardeners and instruct them to not fertilize this area.
There are several ash trees along the north side of the artificial grass:
Dbh’s 5.7 cm.; 4.9 cm.; 4.8 cm.; 5.4 cm. The shrub ground cover is doing well here. The most ominous development is the Algerian Ivy spreading downhill through the fence. If this could be pulled out now it would do good things.
Right along the walkway there is now an abundant growth of a bad weed called Bur Clover (Medicago). This has deep roots and will be difficult to control without herbicides. Digging it up now will save much work later.
My notes say there are three more trees, ashes again, I think, along the east side of the artificial grass. These are in little planter wells and the asphalt cuts down on the amount of oxygen and water the roots can absorb so these are more spindly than the ones to the north:
Dbh’s: 5.7 cm.; 4.9 cm.; 4.8 cm.; 5.4 cm.
Another bad thing is that there is Bermuda grass growing in this area.
Near the steps to the school are three staked Crepe Myrtles (Lagerstroemia indica). I guess they are still staked because of the fear that kids will vandalize them if they stand without their wood protectors. I hope you unstake them, as they will be healthier in the long run if you do. Besides, the stakes are very ugly, which contributes to a cheap look to this area. There are many weeds in this area that could be pulled.
The Monterey Pine (Pinus radiata) that dominates the east side of the park is still alive. That is remarkable. This tree is old and has been showing its age for nearly a decade. I thought the excavations to repave the park would kill it but the tree is basically unchanged since the park renovation. It has some insects in it—Sequoia pitch moth (Vespamima zimmermanni), but these are not fatal. The deadly insects that I expected to see—Dendroctenus valens and Ips paraconfusus—are not evident. There are numerous cones on the sides of branches, usually a sign that the tree is in decline, but it’s been like that for as long as I can remember. This tree seems ready to die but it might take twenty years to happen. Would anyone consider planting a replacement now so that a partially grown tree would be ready when this specimen croaks?
Tenth Avenue
2701: The big thing here and all along this strip is Algerian Ivy. If this weed isn’t dug up now it will soon spoil this entire landscape!! It will overtop and smother the nice California lilacs (Ceanothus) that were planted. My notes say there is one severely pruned red oak here.
2617: My bit thing here are the red oaks that were planted (at my urging). They are still staked. These stakes will weaken and, perhaps, kill these trees. I beg of you to remove the stakes ASAP. Contrast these trees with the ones on Eleventh Avenue, where the stake were removed within a few weeks of planting. These oaks are in much worse shape than the ones on Eleventh. The bark is roughed up by stakes rubbing against the trunks. Lower limbs have been broken off. These trees are a mess. Removing the stakes will give them a new lease on life.
My notes say there are some exposed sprinklers here that are ripe for being vandalized. Actually that might not be a bad thing. This are probably should never be irrigated. The Ceanothus will do much better if left dry. And lack of water will slow down the growth of the Algerian Ivy.
I also noted lots of weed grasses here.
2615: There’s a volunteer palm tree right next to the sidewalk that should be dug up. Algerian Ivy is the big problem here.
One interesting question. Right here are two volunteer native plants (Baccharis pilularis), Coyote Bush. I think they are ugly. Their flowers are highly allergenic. But they are California natives. I would remove them but I can see why you might not want to do that.
2609: See the street trees on this block? Grevillea robusta, She Oaks. They are not oaks and I think most residents on this block regret choosing them as street trees. They are messy and they break sidewalks. I note this because there are a few volunteer Grevillea’s in this area. One is opposite 2609. These should be dug up now before they break the sidewalk!
There is also a Pyracantha here that doesn’t belong, probably seeded in by a bird. It is thorny, prone to insects and harbors Fireblight. I think you should remove it.
2535: Lots of Oxalis here. It’s been weeded recently and will need to be weeded regularly. There’s also a volunteer red oak growing here that should go.
Here are the Dbh’s of the three Red Oaks that are so badly staked:
2615: 5 cm.
2609: 4.1 cm.
2609: 3.8 cm.
2609: 2.7 cm.
2535: 4.8 cm.
One thing that staking does is to make trees thinner. Thus the Dbh’s on these trees are half what they should be by now.
