How to "grow" a natural privacy screen
The (real) Curiosity Vine - experiment and growth! - The experiment that inspired our name.
This is an ongoing vine planting and growth experiment to help understand how it grows, how it covers, how to protect it, and how to make it happy! The objective is to
cover a relatively small, defined area;
In a heavily shaded area;
In the mid-Atlantic U.S. environment.
It is also to learn and enjoy the growing habits of a plant genus as the experiment unfolds. Perhaps calling this an experiment is a bit of a stretch. There is no control group. This is more of an exercise in regular and detailed observation.
Boston Ivy (grape) experiment.
Description and Background
Parthenocissus tricuspidata is a flowering plant in the grape family native to eastern Asia in Korea, Japan, and northern and eastern China. Although unrelated to true ivy (like helix), it is commonly known as Boston ivy, Grape ivy, and Japanese ivy, and also as Japanese creeper, and by the name Woodbine. Northeast private colleges are known as the “Ivy League” received that name from the Boston Ivy. The Boston ivy is known to cover the associated academic buildings. The covering has the effect of external cooling insulation, absorbing heating sun rays and helping cool the buildings during the warm summer. Also, Wrigley Field, a baseball field in Chicago, has an outfield wall covered in Boston ivy.
I chose it because of its known hardiness and appropriateness to the local hardiness zone, tolerance of some shade, and ability to creep to cover a lattice wood wall. (Built as an AC unit screen) I built the lattice fence with my son, David. It was a low-cost "Home Depot" project, consisting of wood lattice panels, 4x4 wood supports, concrete to anchor the supports, and trim wood to fasten the lattice to the supports. Finally, after assembling, we painted it with outdoor paint using a paint gun (rather than a brush). It was a fun and pretty easy father/son project!.
Grape is deciduous and known to turn red after a fall frost. Also, the shoots adhere using a light enzyme adhesive ( vs. a burrowing anchor of the helix genus) so less destructive to the lattice wall.
The location is our home in Great Falls, VA near Washington D.C., hardiness zone 6b / 7a. The area is next to our house, southeast facing, with heavy shade from a large Crape Myrtle tree and a small pavilion. Some direct sunlight comes for an hour or 2 at sunrise, before the sun clears the pavilion and tree.
Purchased 6 small grape plants via online retailer and delivered live via post, from Hirt’s Gardens.
Planted May 17, 2019
Small and healthy
Planted in 2 window boxes in a very shady area.
The intent is to cover lattice wood AC unit screen and to constrain growth via limited root growth area (root bound) and active stock pruning.
Potential Risks: 1) lack of sunlight, as it is located near the house, under large crape myrtle, and near a small pavilion. AC fence faces south and east sky. 2) root temperature exposure, possibly from lack of window box insulation will be problematic given winter temps.
The grape has more than doubled in size and taken to creeping up the fence. The longest shoot has reached the 1-foot mark. One of the plants started turning red but is returning to green. The red turn was presumably from the stress of mail and transplant.
Activity: watering to need and active diversion of creeper shoots. Probably should minimize disturbing shoots in favor of nature’s choice.
The grape has grown significantly. 3 x in height. The longest shoot is just shy of the 3-foot mark. While accurately measuring the biomass is difficult, it has grown significantly, with multiple shoots growing from the base and the stock of more mature shoots. The feet are very interesting. They grow from the shoot to attach themselves to the wall. There is an adhesive enzyme that adheres to the feet. The enzyme does not appear to be toxic to the wall surface but is a strong enough adhesive to hold the vine. The feet extend until wall contact is made and the enzyme bond is made. Then the feet appear to coil. The coil may be natural dehydration intended to draw the vine to the wall surface. I’m curious how the feet know the direction to grow to attach to the wall surface. They appear to have some sense that draws them toward a stable surface to support vine growth. The vines in the right pot are growing faster than those in the left pot. Potential environmental factors include light, the right pot is getting a little more light. Also, the right pot may be getting a little more water.
Activity: Watering and some light shoot diversion, though I am trying to minimize interference. I will consider pruning lead shoots once they reach the edge of the wall. Am curious if vines have apical and lateral meristems that behave similarly to other plants (I.e., prune an AM and the LM’s will activate further down the stock). This month I purchased several burlap bags, in anticipation of filling them with insulating biological material as root insulation. Will put in place at first frost.
Added Osmocote fertilizer in the 2 grape pots.
Pruned first lead runner (AM) as it passed an edge. Observe to understand if LMs activate/grow more vigorously.
The Grape continues to grow quickly. Hard to say in terms of height or biomass the growth scale. The longest shoot was cut at 5 feet. It does appear lateral shoots or LMs did activate after the prune. The activation was near the end. The theory being that these are “replacement” AM, not so much activation of LMs further down the vine.
The fastest shoot from the left box has now exceeded the 5-foot mark. The left lattice wall is 6 feet high.
I have noticed certain shoots grow much slower. Fast grower shoots have a reddish hue in both the stem and leaves. The color fades to green as time passes. Also, the slow grower shoots do not have a reddish hue. The slower-growing shoots are also associated with shoots that grew under the lattice. Could this impact growth (impeding photosynthesis?)
Also, hard to tell the fertilizer effect. Possibly should have tried some kind of RCT. Since there are only 6 plants and the conditions of each plant vary, not sure how useful this would be.
Watering and light shoot diversion.
Am interested to see how dropping temperatures affect the plant. Daily Temp ranges last couple days 58-84. This compares to warmer ranges in June, July, and August.
Also, am interested to see if extra light once crepe myrtle leaves drop is a factor. Since this is confounded with temp drop, not sure if the effect will be determined.
For winter care, insulation was provided to protect the roots exposed to winter temperatures. This was done by packing burlap bags with organic material as a buffer. No testing was completed to determine the effectiveness of the treatment. While the effectiveness is unknown, the cost is low. As such, considered a low-cost precaution. The precaution was put in place in mid-November as evening temperatures were dropping below freezing.
As of 3-17-20, all 4 plants are showing signs of complete winter survival as buds are showing on all stems.
Boston Ivy health and growing. I have pruned leaders several times as they extend past the lattice fence. As expected, apical / lead pruning encourages lateral growth. Also, I noticed the development of different leaves. Some leaves are 3 separate leaves growing from a leaf base. Others are a single 3 forked leaf. Not sure why the difference.
Upon reflection, I should have dug a trench to set the plastic planters. This would have used the ground for root insulation in the winter while maintaining the root spread control.
3 separate leaves
The growth rate of the grape has slowed. Evidenced as 1) the existing shoots' daily growth has slowed, and 2) the production of new shoots has slowed.
It has been a relatively cool spring, which may affect the growth rate.
Theory: there is a ratio between the geometric area that roots have to set and seek nutrients to the total biological mass it supports above ground. Perhaps the plant is starting to reach some root system support limit. As it approaches this limit, the foliage growth slows given the available nutrients from the root system.
If true, this would validate my attempt to limit the grape’s overall growth area to the wood lattice by binding its roots in a plant box. (A lazy man’s bonsai)
Also note, the plant is most dense at the top middle of the 2 lattice sections. This is likely because the topmost lattice pieces are angled toward the middle. The plant shoots naturally travels to the area of least resistance as dictated by the environment.
An update to the 6/16/20 entry. While I still agree the growth in individual vine leaders has slowed, the total number of leaders has increased. As such, this questions my biomass to root mass ratio theory (BMR theory)
The theory may be sound, but I’m not sure if this is actually the case currently for the vine. Meaning, the slowing of individual leader growth may be because of a swap in plant energy to support multiple leader production. Not an indication of meeting a BMR limit.
The weather is turning, with cooler nights and days. A couple of leaves are starting to turn color, but nothing significant yet. Just by observation, the difference between the June and October photo is significant. The vine is filling in substantially, with many smaller shoots growing from their older parent leaders. I suspect next growing season, the supporting white lattice may be covered by the dense green of the ivy. I have been regularly watering the ivy, though as it gets cooler, the watering needs are less.
I do anticipate insulating the root boxes similarly to last winter, with biomass in burlap bags. I am annoyed with myself for not thinking of digging a trench in the ground to hold and naturally insulate the root boxes.
As indicated in the grape descriptions, the leaves are turning reddish as the temperatures drop in the fall. The color change began in the 2nd week of October. The lack of color uniformity is curious. Not sure why some leaves or vine shoots have turned faster than others. It appears the vine shoots associated with the right box are very actively turning color, whereas the right associates are not. Perhaps water is the difference?
This has been an especially warm March week, sunny with highs in the upper 70 degrees Fahrenheit. The grape is starting to bud, with its normal small red buds appearing at the ends and junctions of the vine. The budding appears well distributed across the grape, with no section death observed.
Last winter, I did change the root insulation. I only covered the side more exposed to the wind. My thinking was 1) the grape is more mature and 2) my increased comfort with its hardiness.
Leaf size approx 1 inch
no vine growth
Leaf color red
Spring is springing, with days in the mid-70s. Overnight lows are generally in the 50s with periodic drops into the 40s or even upper 30s. Last year, around this time, we did get a hard freeze, with a few days in the 20s. This wreaked havoc on the leaf production of a few of our trees (Japanese Maple and Star Magnolia). Luckily, the freeze did not kill the plants, just made leaves less abundant last year. In general, this freeze did not appear to impact the vines.
I have heard that global warming while making small increases in average temperature makes big changes to temperature volatility. Meaning the extremes have increased for both high and low temperatures. I tend to agree. See this post on Cherry trees that gets at higher temperature volatility driving earlier blossoms based on data kept over a millennium!
The vine buds have opened and the initial leaves have formed. They are the small baby leaves that will grow substantially during the growing season. Also, the vines themselves have not started to grow, only the buds and leaves on existing vines. This suggested the plant energy is primarily dedicated only to leaf production. Perhaps this is like energy bootstrapping. Meaning, there is just enough energy from the root system to initiate leaf growth. Once the leaves get to a certain size and number, leaf photosynthesis takes over as a primary energy source, providing for vine growth. I’m guessing there is some relevant ratio of plant leaf biomass growth support to available energy. Perhaps the ratio stays relatively constant but the denominator bootstraps the numerator. In effect, it is like a growing recursive loop, with the energy denominator pulling along the leaf production numerator, that creates more energy for the denominator.....(loop continues). You may ask, what even kicks this off? Why does the plant want to grow in the first place? Perhaps, this is related to entropy. That is, the plant is compelled via physical law to move from the highly structured dormant state inside its root system to the less structured space around it. It is the warming, moist, and fertilized environment that acts as an entropy catalyst. Think of the root system and fertilization as a store of potential energy. It is the warmth, along with the moisture and other environmental factors that “unlock” the potential energy and transform it into the kinetic energy associated with plant growth.
initial vine growth (with feet)
Leaf color turning green
The temperature this week was good for cool weather plant growth. The 60s in the day and 40s at night. Plus significant rainfall.
Before discussing the vine, allow me to take a brief grass diversion.
Our lawn contains cool weather grasses like tall fescue. It is a tricky grass because of how it responds to mid-Atlantic temperatures and moisture. Talk fescue generally likes the cooler temperatures of fall and spring. It goes dormant in the winter and survives the summer with some help. To some degree, the actions of the fall-winter-spring are preparatory for summer survival. If we do this correctly, year over year, the lawn becomes stronger and more resilient. The early spring is a big growth time. It is also a great time to crowd out perennial and annual weeds. I have a 2 step approach to spring weed management. 1) I weaken the weeds with a defoliating weed killer. These weed killers defoliate the above-ground biomass but leave the root system. 2) By growing grass at the same time, I create a thick shade canopy over the weed root systems. The lack of sunlight will keep photosynthetic energy from getting to the root system and causing the root system to die from a lack of energy. The key is having a strong stand of grass to enable the crowding-out approach. Back to the vine...
The leaves doubled in size, plus more new leaves are growing. The leaves transitioned more from red to green. Green is the color of photosynthesis. Chlorophyll is building and the resulting photosynthetic energy is building.
With the initial growth of vines, it appears energy bootstrapping is occurring. The transition is occurring from root-based chemical energy to leaf-based photosynthetic energy. The leaf-based energy contains higher energy levels and will drive higher growth. The leaf to energy ratio appears consistent and growing.
Next are 2 picture perspectives, a close-up and a big picture. The first picture close-up shows new vine and feet growth. They seem to go together. This makes sense because the new vine needs to be anchored by the feet. My question is, how do the feet sense and grow toward the anchoring surface? Perhaps it is the opposite way of the sun, as coded by DNA and many millennia of natural selection? The second picture is the big picture. The growth of the leaves seems to be covering much more of the lattice from last week.
3 - 4 inch leaves
Vine actively growing (with feet)
Leaves mostly green with a few deep red left
The temperature this week was volatile. Mostly in the 70s / 80s. One day had high winds and high temperatures in the 50s and 60s. Lows were above freezing.
The same leaf we have measured for the last month is now over 3 inches wide with the typical green color of a mature Boston vine leaf.
The overall lattice wall is about 70% covered. I am seeing vine shoots moving toward the open spaces. I have also trimmed some shoots that are growing off the lattice. Given a fixed amount of photosynthetic energy, my theory is that pruning will leave more energy to the rest of the plant. Thus, pruning areas you don’t want will leave more energy for the areas you do want.
3 - 4 inch leaves
Vine actively growing (with feet)
Leaves mostly green with a few deep red left
The initial stage of growth from seasonal dormancy is just about over. The leaves from existing vines are full size or nearly full size for the season. I will continue to track the same leaf. While I predict it to continue to grow some, I expect its growth rate to slow dramatically. As such, plant energy usage will turn from growing the leaves / solar collectors from existing vines. The energy usage will now be dedicated to using mature leaf energy to grow vines and new leaves. Another step in the energy bootstrap. The energy from the roots is still available, but the root energy (nutrients) and hydration will support the more abundant leaf-based energy to grow the vine.
Interestingly, this week, the proximate Crape Myrtle leaves have come in. It is amazing how quickly they grew. The Crape Myrtle leaves have gone from non-existent to almost grown to full size in under a week. This has a significant impact on the grape for 2 reasons:
The sun energy available to the grape will fall significantly because of the Crape Myrtle shade. Instead of the sun for over half the day, now it will only get 1-2 hours in the morning, then a little dappled sunlight for the rest of the day.
As it gets hotter, the shade will protect the vine from the heat of the day.
Back to the bootstrapping comment, this may slow the growth of the vine, though the protection is likely a good thing as we move into the summer months. Also, it would seem the initial growth in grape leaves to almost maturity is well-timed with the Crape Myrtle leaves. It is like the Crape Myrtle knew to hold off leaf production until the grape leaves got established enough that the grape could make do with less sun. Evolution is a wondrous thing! The following picture is the mid-morning view from the grape.
The vine continues to grow and become denser. My care activities include redirecting new vine leaders to open spaces on the fence, plus, pruning those growing off the fence. This takes very little time. Also, as the season gets hotter and dryer, periodic watering is needed.
Also, we just finished an intense 3 weeks of our 17 year-periodic cicada infestation. Other than resting on a grape leaf, the cicadas did not seem to impact the vines.
I have decided to pivot the growth boundaries of the screen. To this point, I had been regularly pruning plant material that grows past the boundaries of the screen front. Mostly with the intent to manage available growth energy to parts of the plant closest to open areas on the screen, thus accelerating the “greening of the screen.”
Now that the screen is mostly green, I’m relaxing that requirement. I’m particularly interested in Ivy bridging the gap from the screen to my house. I thought it would be interesting to have Ivy growing on the side of the house. We will see! I'm especially interested in what my wife will think.....