How much to water

Asked June 23, 2020, 5:17 PM EDT

I had ten Skip laurel – Prunus laurocerasus ‘Schipkaensis' - planted two weeks ago. What is the proper watering schedule to follow now?

Anne Arundel County Maryland

1 Response

There is no schedule per se for the watering itself, only regular monitoring. Feeling the soil moisture by hand is the best way to gauge when they need water. Of course, rain patterns, air temperatures, humidity, and wind will play a role in drying rate and the need for supplemental moisture. Soil type and level of compaction, while a constant, also influences how quickly water is absorbed, drains away, or remains locked in soil pore spaces.

Near the roots, feel the soil a trowel's depth down. If adequately moist, soil will feel cooler, probably look darker, and easily stick to your fingers. If drier, soil will feel warmer (closer to the surface temperature), not look darker, and more easily dust off your skin. The root area should be soaked well when needed but infrequently enough that the soil isn't staying constantly wet. By letting the drying-out process begin, it allows some of the soil pores to "recharge" with oxygen, which healthy roots need. This is why over-watering is problematic for plants not adapted to wet habitats: the pore spaces in the soil that hold some oxygen are filled with water instead, and the roots essentially suffocate after prolonged exposure. Soils that dry out too much can result in wilting, but if you see this symptom, check the soil first anyway, because this can be deceptive - over-watered plants (and other unrelated causes) can also wilt. (Since the roots are dying, they aren't supplying water to the top growth, so in effect, it's the same as being water-deprived.)

The only pattern, really, is that a good root soaking should be followed by a period of waiting for the soil to dry enough. If there isn't any rain for awhile and it's hot out, given that these are new plants, this might mean a once- or twice-a-week watering; perhaps more if your soil is more sandy than clay-based. A mild, lengthy rain is good, but a drizzle or passing drenching rain might not help much, because it isn't going to soak in well and instead run off or evaporate too quickly. This is why it's just easier to get in the habit of feeling the soil before watering. If you are using a hose to water these shrubs, using a water breaker to turn the spray into a gentler "rain" is very helpful to avoid eroding soil or using too light of a mist. You may need to soak briefly, move on, and come back to a plant once or twice more to ensure the water seeps in instead of draining elsewhere.

Miri