A Guide for Watering the Newly Planted Shrubs (2017)

A Guide for Watering the Newly Planted Shrubs, by Ian A.Reid

This article specifically refers to the 10 shrubs that were planted near the picnic tables in the spring of 2017. The results of the recommendations can be used for other nearby plants (shrubs) as well.

These shrubs evolved over centuries without human interference. So the question is when should humans interfere with Mother Nature?

People cannot control the amount of rain for this area or any other area. If the soil is waterlogged for an extended period, the plants die. e.g. when a reservoir is created, the trees in the reservoir die for lack of oxygen. Likewise. If the roots of shrubs are waterlogged for an extended period, the shrub dies for lack of oxygen. The other extreme condition is drought over extended periods of time. Here it takes a long time for the plants to die because through evolutionary mechanisms the plant prolongs its life. So people should only intervene with Mother Nature when the normal rainfall amounts for the area are in a deficit situation except for newly planted plants when extra water is beneficial.

So what is the normal rain fall amount for this area? For this, we find that the Environment Canada’s Macdonald – Cartier station is the closest weather station to the site where the shrubs are planted.

The Government of Canada lists the monthly precipitation data for the Macdonald – Cartier Weather station in millimetres (mm), are as follows:

	Feb.	Mar.	April	May	June	July	Aug.	Sept.	Oct.
Monthly Precipitation (mm)	54.3	64.4	74.5	80.3	92.8	91.9	85.5	90.1	86.1
Average Weekly Precipitation (mm)	13.6	16.1	18.6	20.1	23.2	23.0	21.4	22.5	21.5

This is how roots behave after, say, a 20 mm rainfall. Because of gravity the water table gradually lowers. As the water table lowers, the roots follow the water table down to obtain nourishment. This is the normal action of roots and this regime develops a strong deep root system. When gardeners water their plants every day, the roots stay near the surface because they have lots of water. This is not a normal situation, and the plant develops a shallow root system.

I’m going to plant a rain gauge in the middle of the newly planted shrubs. The gauge will be read Fridays of each week. If there is a water deficit compared to the normal precipitation as indicated from the table above. Water will be added to make up for the deficit. By following this regime the shrubs should develop a strong deep root system. This regime of watering to make up for any deficit is especially important during the first year after transplanting. It’s not so important in subsequent years because of the strong roots developed in the first year after transplanting. If in the second year after transplanting a mini or major drought occurs, the plants should definitely be watered to at least normal amounts of water as indicated by the table above.

Now, let’s solve a hypothetical example. The rain gauge reading on a Friday showed that there is a 5 mm deficit of rain when compared to the Macdonald – Cartier weather station. This means that 5 mm of water has to be added to each of the 10 shrubs to bring the water table up to the recommended level. Since Environment Canada lists precipitation in millimeters (mm), we’ll do the calculations in mm.

For each shrub, we must add the following amount of water by bucket or hose:

Each plant is planted within a circular area covered by mulch. This area is to be watered and we need to first determine the circle area. The area of a circle, A, equals Pi times the circle’s Radius, R, squared. Pi is a constant that is close to 3.1416. This is written A = Pi x R x R. The circle diameter was measured to be 4 feet (or 122 cm). Therefore the circle radius is half that (61 cm). Because rainfall is measured in millimetres convert this to 610 mm. The resulting circle area is 3.1416 x 610 mm x 610 mm = 1,700,000 mm2. We’re adding water, 5 mm in depth so the volume is 1,170,000 mm2 x 5 mm = 5,845,000 mm3 (cubic mm). Let us just say it is 5.8 million mm3. Now, 1 litre contains 1 million mm3. To determine how many litres of water are needed, take the amount needed, 5.8 million mm3, and divide it by 1,000,000 mm3/litre. Conveniently, the answer is 5.8 litres (notice, it is the same number of litres as the number of millions mm3). Further simplify buy rounding up 5.8 to 6 litres. The calculation indicates that 6 liters of water distributed equally within the circle has to be added to each shrub to bring the water table up to normal.

This water can be added by bucket (pail) or hose. If the water is added by a bucket, simply add 6 liters of water in the bucket and spread it carefully to each shrub.

If the water is added by hose, the hose must be calibrated first as follows:
Step 1. Choose a close by hose and stretch it out as it will be used to water the shrubs. The same configuration must be used every time the shrubs are watered to maintain the same calibration. This calculation assumes that the water pressure at the source remains constant day after day. i.e. turn the tap the same number of full turns each time, or just open it to maximum each time.
Step 2. Record the time it takes to fill, say a 20 liter bucket (pail). Any watch that can measure seconds can be used to measure the time. Let us say that with our tap opened to the maximum it took 32 seconds to get 20 litres of water.

Now, from the example above, we must calculate the time it takes to fill a 6 liter container.

The calculation: 20 liters = 32 seconds (time to fill a 20 liter pail). That is a rate of 32 seconds per 20 litres - this is 32s/20litre = 1.6 seconds/litre. If 6 litres are needed, multiply this number by the rate. i.e. Time to get 6 litres = 6 liters x 1.6 sec/litre = 9.6 seconds. That is pretty close to 10 seconds, so say it is 10 seconds.

If the hose has a different configuration, even a slight kink in the hose makes a difference in the calibration, than in Step 1, the hose must be recalibrated. Hopefully, a nozzle will be on the hose that will deliver a gentle shower of water on the shrub, a hose without a nozzle under high pressure could damage the area around the shrub. This kind of watering is a NO-NO.

I must confess that I’ll probably add a little more water to each shrub as indicated by the calculations above to take care of evaporation.

When this planting and watering regime is followed, these shrubs should thrive for their whole life span that could be for up to 50 years.

Comments are welcome.

Take care,
Ian A. Reid BSc (f) UNB ‘49

NOTES:
Conversion factors:
1 inch = 2.54 cm
1 foot = 12 inches
1 cm = 10 mm

Reference:
Government of Canada weather station at the Macdonald –Cartier International Airport

Acknowledgement:
The author wishes to thank Craig Hamm for suggestions and assistance with the final edit.

A Guide to Planting Shrubs

A Guide to Planting Shrubs, by Ian A. Reid

I have watched several videos on the subject of “Planting Shrubs.” All the videos, I watched miss two essential steps. The missed steps are the first two listed below, as follows:

1. Determining height of the root crown; the root crown is the point of the shrub between the top of the roots and the start of the stem.

It’s very important that this point is one inch above ground level. How do we determine the height of the crown? After the hole for the shrub has been dug, lay a pole from one side of the hole to the other side intersecting the point where the crown will be positioned. Adjust the heights of the crown (where the roots start) one inch above the ground level by putting or taking away soil at the bottom of the hole. To make sure the soil is compacted, tamp the soil down by your feet or by some other means. This removes air pockets and prevents the shrub from settling over time. If this is not done, over time the crown could sink below ground level. (Hint: a good way way to tamp the soil around the roots is to place the plant, fill the hole at least partially full of water and then add the soil.  As the water is absorbed and flows away into the ground, it pulls the wet soil into the holes around the roots, getting rid of air pockets.  Also, you aren't pounding around on top of the roots.)

Before placing the root ball in the hole, scar the root ball say every six places around the ball by some instrument. The scar should create gullies about one inch deep. We have pruning saws in the southern shed that will do an excellent job.

If the sides of the soil are compacted, break up this soil with a shovel or pick before planting

2. Before digging the hole for the shrub, place a tarp on the ground near the hole to prevent the soil from the hole escaping.

Once the soil is on the tarp, remove all weeds and big rocks. Small rocks (stones) can remain. Mix removed soil from hole with compost from the compost pile near the winter storage area .The back fill should contain up to 10% compost well mixed with the soil from the hole. Before backfilling it’s OK, but not necessary, to add a little Bone meal, No other fertilizer is to be used as it may damage (burn) the delicate roots. The roots just before planting could be soaked in water for say 30 minutes.

To check that the shrub is vertical, Use a plumb bob to line up the plumb line with the stem of the shrub. Do this again at 90 degrees to make sure the shrub is vertical. The plumb bob could be hand made by attaching a weight at the end of a piece of string. The weight could be a small stone. Stand back 10 feet or so to check that the shrub is plumb.

3. Diameter of hole. As a general rule, the diameter of the hole, for ease of work, could be 2 to 3 times the diameter of pot. E.g. If the pot is 12 inches in diameter, the hole could be 24 to 36 inches in diameter.

4. Mulching: Mulching suppresses weeds from growing and the water in the soil from evaporating. The mulch should be no more than 2 to 3 inches thick. Never mulch near the shrub’s crown; leave this space clean. The roots have to breathe. Mulch that is too thick, suffocates the roots. Mulch covering the root flare restricts oxygen from the root system, possibility causing the shrub to rot and die.

5. Planting shrubs in a straight line. We have string and a measuring tape in the northern shed ready for use.

6. Spacing: The space between the shrubs should be such that when mature there is a little space between the shrubs.

As a rule of thumb, 15 feet (5m) should be OK for the taller shrubs. A lesser distance for smaller shrubs should be used. The shrubs spread at maturity can be found in Wikipedia.

7. Watering. Watering especially during the first year is very important. The potting mix probably dries out faster than the soil in the hole because the potting mix is not real soil but a mixture of other stuff.

After back filling the hole, the soil should be lightly tamped (not compacted) to get rid of air pockets and then thoroughly watered.

This watering should be repeated every two weeks or though out the growing season.

 I feel somewhat responsible for the NAGA shrubs because first, I planted, at no cost to NAGA, the 20 or more shrubs in about 2000 that were removed to facilitate the upgrade to the Hydro Facility in the South East corner of NAGA, and second, I negotiated with the Chief Engineer in charge of the Hydro’s upgrade to get the $600 to replace the shrubs removed.  If I hadn’t contacted the Company doing the upgrade, we would have not have received any money from the Company. The Company thought that the shrubs belonged to the City.

If the above suggestions are followed, these shrubs should flourish for many years.

Closing Thoughts

I have no idea how many shrubs $600 will buy. This money does not all have to be spent this year. If more money is needed to complete a Master Plan, perhaps it could be provided by NAGA.

I’m suggesting that a committee of interested gardeners be formed to prepare a Master Plan to include not only shrubs but also items like flowering bee beds in bright sun and in the shade and also the placement of Park benches.

As these shrubs grow it will be nice to sit in the shade watching the bees and birds going about their business. Many of our plants depend on bees (honey and bumble). Last summer because of the scarcity of bees, I had to hand pollinate a few plants. In addition my Mason bee house was unoccupied.

When choosing the specific location for the shrubs, remember that the grass will be cut around the shrubs. Please leave room for the big and small mowers to maneuver.

Take care,
Ian A. Reid, NAGA gardener

[Conversion factor: one inch = 2.54 cm ]