Irrigation for a Small Boxwood Hedge

Asked May 18, 2016, 8:15 PM EDT

Hi, I'm about to plant 20 boxwoods (Boxwood Green Velvet) as a small hedge. It will be planted formal style, in the form of 2 rectangles with a small Redbud in the middle. Boxwoods are currently 7" tall. I will keep them to 3' t. x 2' w., I think. I will plant 20" apart. What do you advise for irrigation?
How about the Redbud (grows to 10't.x7'w). It will be surrounded by boxwoods. On the sides it will be 2-1/2' from the boxwood center, in the front and back it will be 3 1/2' from the boxwood center. What do you advise for irrigation? I'm in California, Zone 9, clay soil, with 4" of woodchip mulch, summers will be 70-90 degrees. House will provide shade in the late afternoon. Thank you! Appreciate your help.


Contra Costa County California irrigation landscape plants horticulture

3 Responses

drip irrigation is the only way to go. Clay soil absorbs water so slowly and drip irrigation applies water slowly and low pressure, so you will have more success with drip irrigation. Spray irrigation applies water faster and under higher pressure than clay soil will absorb it, so there is a lot runoff and evaporation. With the water shortage continuing in California you must use the most efficient/conserving irrigation method possible and that's drip irrigation.

Thank you. I have 3 questions about drip irrigation:

1. What size emitters should I use for small boxwood hedge. 1/2 gph. or 1 gph.

2. Should I set up 2 emitters per boxwood?

3. Should I put emitters on both sides of the boxwoods, or should I put them inbetween each boxwood? I was planning on planting the boxwoods 2 1/2' apart.

Thank you.

Lori


Lori

  1. What size emitters should I use for small boxwood hedge. 1/2 gph. or 1 g ph.

By giving me this emitter rate, I think you are speaking about inline drip irrigation tubing which has built-in emitters at 12” or 18” spacing. Point source drip irrigation uses tubing with no built-in emitters. For point source drip line, you punch a hole and insert the emitter of your choice. Therefore you can have an emitter at each plant and choose the gph rate you want. You are not limited to ½ or 1gph.

Choosing an emitter rate and spacing has to do with the soil and plant water requirements. Clay soil absorbs water very slowly and sandy soil absorbs water very quickly and runs straight down. In both cases, use the slowest emitters, 1/2 gph. This allows for slow absorption in the clay soil and will allow the roots in sandy soil more time to absorb the water instead of the water running through the soil.

2. Should I set up 2 emitters per boxwood?

You can do this pretty precisely with point source but with inline drip tubing you attach the tubing and the spacing is determined by the emitter spacing. If using inline drip tubing, the spacing is not as precise but it will work and there is not the worry of the emitters stopping up particularly if you use drip irrigation filter at the water source.

If using point source, place one emitter at the base of each plant. This is how vineyards do it. I do this in my rose garden. Not up against the trunk. Clay soil moves water horizontally so the emitter does not have to be too close but sandy soil the water runs straight down unless you have added good compost to the sandy soil. Compost will absorb the water quickly and release it to the plant roots. You also want to be able to check the emitters for blockage if you have calcium in the water. I check mine once a year when I cut back my roses.

3. Should I put emitters on both sides of the boxwoods, or should I put them inbetween each boxwood? I was planning on planting the boxwoods 2 1/2' apart.

One emitter per shrub underneath each shrub if using point source on clay soil. Use two emitters if sandy soil. If suing inline tubing do not worry so much about the spacing pre shrub. Use the 12” spacing in the line and 12” between tubing. So at 2.5 inch spacing, yes you will have tubing on each side of the shrub. Visit any of the rip irrigation web site. They have great tutorials.

http://www.netafim-usa-landscape.com/ http://www.digcorp.com http://www.rainbird.com/drip/index.htm http://www.toro.com/sprinklers/guides.html