Now that we have entered the summer months, the spring planting season has drawn to a close. That doesn’t mean that we need to stop planting. One of the great benefits of plants growing in pots is that they can be planted at any time of year.
This is very different from 30 or 40 years ago, when a lot of plants – evergreens in particular – were grown in fields and dug out of the ground in spring or early fall, and then sold for immediate planting. This change doesn’t mean, though, that we can treat summer plantings the same way as we might a spring or fall planting. While bargains are often available in summer, as nurseries clear their remaining spring stock, they can need some additional care, if they are to succeed, and not suffer any set-backs. Let’s look at the way to handle summer planting of evergreen bushes, such as Thuja Green Giant, Emerald Green Arborvitae, or any of the multitude of ornamental evergreens available to us.
Care of Evergreens Before Planting
Once your evergreens arrive home, either from a shipping delivery, or from a shopping expedition to a garden center, you need care. In spring or fall we can often just put them in the garden for a few days, and more-or-less leave them to their own devices. Not in summer.
Shade is best
Find a shady spot in your garden, and unwrap the plants immediately, including any string that has been used to hold them together during shipping. If you have bought several, perhaps for a hedge or screen, then space them out a little, so that the air can circulate around them. Close packing can lead to yellowing, or fungal diseases.
Water the pots thoroughly, so that water drains out through the holes in the bottom of the pot. Do not stand them in saucers – let the water run away into the ground. If you are not planting for a few days, check the root balls each day, and water if the top inch is dry.
Shade the pots
Sometimes, in a new garden, you may not have a shady area available, since you have no large trees yet. There may be a zone of shade along a fence, or on the north-facing side of your house, but if not, then place them in the sun. In this situation the foliage will normally be fine in full sun, but there is a danger that the pots, which are usually black, will absorb a lot of heat from the sun’s rays. This can raise the temperature inside the pot, damaging the roots. In this situation, wrap some old burlap, or some scrap cardboard, around the pots. If you have lots of plants, arrange them in a block, and put some shading on the south and west sides, which will be the ones that pick up the most heat. Cardboard, or some burlap attached to sticks works well, and so does white plastic sheeting, which will reflect the heat away.
Planting Evergreens in Hot, Dry Weather
Now you have taken care of your plants for the time you need to start planting, we can look at the planting site, and modifications to planting when you are doing it in the summer.
Preparing the planting area
In spring or fall there is usually enough rain around to mean that the soil you are planting into is damp. Often in summer it won’t be, but instead the area will be dry. For good establishment of your plants it is best if the ground is damp, so a day or two before planting, arrange for a thorough watering of the whole area, not just the planting holes. If you plant into dry soil there will be no encouragement for the roots of your plants to spread out, even more if you keep the root ball watered, so the surrounding soil needs to be damp too.
The best way to do this is to put a sprinkler on the whole area for a few hours. If you stand with a hose you may simply wet the top couple of inches, without their being time for the water to penetrate. By doing it a day or two before planting you leave time for the water to drain down, and you won’t be planting in mud. Especially if you have clay soil, allow two days for it to drain well.
(I am assuming here that you have already dug or rototilled the area and added organic material to the soil, as we have described in lots of previous blogs)
Prepare the plants
The night before you plant, give all the pots a good soak. That was easy!
Planting time is here
Finally, we get to do the planting. Since you have already prepared the area, just remove enough soil to fit the pot. If you are planting into soil that has not been prepared, take out a hole three times the diameter of the pot, and mix some organic material into the soil you removed from the hole. Just dig the hole to the depth of the container, and roughen up the bottom with a digging fork, or spade.
If you are planting several bushes, don’t remove them all from the pots before starting. The delicate roots will dry and burn quickly in the hot sun, or dry wind, and die. Only remove the pot when you are ready to immediately put the plant into the hole.
Put back two-thirds of the soil, and firm it down around the root-ball. Now fill the hole with water, and let it drain away completely. Replace the rest of the soil and firm it down gently.
After you finish planting, water the whole area well, and add a layer of mulch – organic material like compost or manure, or shredded bark, are better materials than gravel and bark chips, as they will feed the soil as they break down, while reducing water loss from the soil surface. Cover an area triple the pot diameter with mulch, leaving the stem and foliage uncovered.
Caring for Newly-planted Evergreens in Summer
Newly planted bushes are entirely dependent on their root balls for water, until they send out new roots, which can take a month or more. So, in summer, let a hose run gently, close to the stem, for a while, every second day for the first week. The water around the plant over a bigger area twice a week for the first month. After that, water weekly until the end of the season.
Don’t make the common mistake of skipping a watering session because there was a summer thunderstorm. That water rarely penetrates the ground at all – scratch the surface the next morning if you don’t believe it, and you will see dry soil.
To help your plants start growing strongly, use a liquid fertilizer for evergreens every two weeks during this first season. In the following seasons you can switch to granular feeds, which are usually cheaper, certainly quicker to apply, and work well on established plants with bigger root systems that can absorb them.
If you follow these simple steps, you will have great success with summer planting, even in the hottest conditions, and you can take advantage of the reduced prices that are often available. Don’t put it off until the fall, or next spring – get planting now.