So you’ve purchased a plant from our Fall Plant Sale. What happens next?
If you ask ten horticulturists how to install a potted plant you will receive ten different answers, but here we will provide some basic best practices to help ensure that your plant thrives when it is transitioned into the ground.
Get To Know Your Soil
The first step is to get your hands in the dirt! Soils vary widely across the Tucson area and can even differ in the space of a single yard so it is helpful to familiarize yourself with the soil in the areas you plan on planting.
Use a trowel or shovel to scoop up a handful of soil, wet it down, and squeeze it in your hand. If it stays in a clump like play-doh, that indicates a high clay content. If the soil is gritty and falls apart when squeezed then chances are you have a lot of sand. Now try digging a hole the depth of a shovel head and pour some water in. If the water sits without draining that indicates clay or even caliche (a concrete-like layer of calcium carbonate). If the water drains really quickly that would be an indication of sandy soil.
So what does this all mean?
Clay soils, especially those with caliche, tend to have poor drainage which can be a major impediment to desert plants that don’t like to have wet feet. This is especially true of cacti and succulents that are prone to rotting. If you do have clay soils it will be important to deepen your planting hole to break through clay or caliche layers. Additionally, you can add volcanic cinder, pumice, or coarse sand to improve drainage around your plant. For cacti and succulents you may even want to create a mound to plant on so that the plant won’t be sitting in water.
If you have a sandy soil it means that water will drain away quickly which is great for preventing rot but can mean that plants dry out quicker during periods of drought and hot weather. You can help by adding organic matter to the soil in the form of compost to improve the moisture retention capabilities of the soil.
The best move is to select plants that are relatively tolerant of your soil type. Some species such as mesquite (Prosopis velutina), Goodding’s verbena (Glandularia gooddingii), and creosote (Larrea tridentate) are fairly clay tolerant while others such as white bursage (Ambrosia dumosa), smoke tree (Psorothamnus spinosus), and most cacti species will be well-adapted to growing in nutrient poor sandy soils.
Dig Your Hole
The size of the hole you should dig will vary a bit depending on the type of plant and the quality of the soil but there are some general rules that can be followed. Typically a planting hole should be at least two to three times the circumference of the root ball (the main mass of roots directly beneath the stem) of the plant. This will make it easier for the roots to expand outward. The hole can be dug deeper than the root ball to bust through layers of caliche and compact clay but should be backfilled so that the plant is not sunk too deeply in the soil when planted. At the Museum we like to pour some water into our finished hole and allow it to sink in. this pre-wets and settles the soil which will help when the plant goes in.
Install Your Plant
When you set your plant in the hole you want to ensure that it is not planted too deeply. In other words the stem or trunk of your plant should be no deeper than it is in the nursery pot. Trees and large shrubs often have a flare near the base that should be exposed to prevent rot.
Cacti and succulents will usually have a distinct water line where they touch the soil and they should be planted no deeper than that line. Backfill the soil into your planting hole, pressing it down but not compacting too much. When handling cacti, try using barbeque tongs or heavy-duty welding gloves.
Water deeply after planting to help settle the soil and ensure your plant thrives. (What does “water deeply” mean? While this varies by soil type and plant, aim to water slowly over a period of hours so as to soak the ground a few feet deep.)
While water needs vary quite a bit between plants, it is important to keep a close eye on your new plant for the first several weeks. For most shrubs and trees it will be helpful to water every two-three days after planting in cooler temperatures and probably daily during the heat of summer. For cacti and succulents you will probably only need to water once to twice a week during extremely hot weather and as little as once every couple of weeks during cooler weather. While we recommend looking into irrigation for your garden, that’s a whole separate blog post!
Whole books have been written on planting native species but these tips will help you get started on your native plant journey. We recommend looking up transplanting and watering guidelines for your specific plant. You may also want to check out the University of Arizona Cooperative Extension for guidance. Always feel free to ask one of our horticulture staff for advice on how to best care for the specific plant you brought home!
Written by Jack Dash, Botany Staff