How to Prepare Your Garden Bed Soil for Planting Roses
With rose-planting time here or just around the corner for many gardeners, now is the time to make new selections and prepare their planting locations. Gardening expert Katherine Rowe explores how to prepare soil for roses in advance to give them the best foundation.
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With late winter comes rose planting time, and establishing the right foundation in advance gives them a headstart for years of lasting enjoyment. Setting up healthy soil is one of the most important things we can do to promote resilient, carefree performers.
Roses that get off to a good start develop strong root systems, able to withstand drought and seasonal weather extremes like high heat or freezing conditions. With healthy roots, disease resistance, and vigor increase.
Roses grow best in organically rich, well-draining soils. But the flowering beauties are adaptable, and many tolerate less-than-ideal conditions with their hardy constitutions. Mid-winter is a perfect time to make rose selections, sourcing them from growers and nurseries now to plant when conditions are favorable. Basic fixes are best before the rose goes into the ground, and with a few steps, they are easy to achieve.
How Roses Arrive and When to Plant
While we can plant roses any time of year, the best times are late winter, early spring, and fall. The cool conditions and seasonal moisture pose the least stress on the flowering shrub without exposing tender growth to freezing or hot conditions. Temperatures between 40-60°F (4-16°C) are ideal. Avoid frozen or waterlogged ground and drought conditions, which cause stress and hinder growth.
Roses can go in the ground before spring’s last freeze. Six weeks before your final frost date is usually well-suited to planting, depending on your local climate. Keep an eye on frigid conditions, as exposure to freezing soils and air temperatures can cause dieback. It’s best to wait until prolonged low temperatures pass to install new plantings.
Bare Root
Bare root roses arrive dormant and without soil in the cool season. Roots develop at planting as they expand in moist, warm conditions. Upper growth quickly emerges for summer blooming.
Order your picks in advance, scheduling delivery when planting conditions are right so the rose can move quickly into its prepped bed. Knowing your growing zone is important in timing the arrival of bare root selections.
When your bare root selections arrive, soak them for at least two hours (and up to 12) to rehydrate the roots. Then, install them in their pot or garden spot. Some gardeners pot them up for a brief hardening-off period, where they spend time outdoors protected from intense afternoon sun and cold nights before installation.
In Containers
Some delivered roses or those from your local garden center are in nursery pots. Container specimens are available for planting year-round, many in spring, as leaves and stems flush for the season. These don’t need any pretreatment and move easily to the garden.
Workable Soils
While there are ideal conditions for planting, roses can go in the ground anytime soils are workable. Workable means the soil is not frozen or overly saturated and soggy. Avoid rainy, cold days in late winter or early spring if the ground is hard to work with or it sticks to the shovel in large clumps.
These conditions also relate to soil prep days. Opt for a dry day to prepare the soil for roses and incorporate any amendments; bonus if snow or rain is in the forecast later.
Prep the bed before planting if possible, giving any compost a week or more to settle. Rain or snow after prepping is beneficial; the moisture helps amendments infiltrate the native ground. It takes time for nutrition to improve, and even a month or two in advance helps amendments take effect prior to planting.
Ideal Soil for Roses
The best soil for roses is a blend of organic matter and native soils. Beneficial fungi (mycorrhizae) also play a role, naturally or boosted. Roses prefer loose, rich, neutral to slightly acidic soils with a pH of 6.0-7.0. They thrive in well-draining texture with even moisture, but well-developed specimens won’t protest if conditions are less than ideal.
Roots follow water, nutrients, and oxygen available for uptake, and healthy compositions provide ready access to each. At planting, add three to six inches of compost, especially in poor dirt like clay and sand. Compost helps with aeration, moisture retention, drainage, and nutrition.
If the bed is prepped and ready, dig a hole six to eight inches larger than the root ball to comfortably accommodate all roots and loosen the surrounding ground. If the bed is new or not prepared before planting, dig a hole twice as wide for amending and planting. Remove sticks, rocks, or other impediments that may obstruct roots. Add compost to incorporate when digging and filling.
Organic Matter
Aim for one part organic matter to two parts native soil for a balanced loam to start roses. At least half of the composition should be friable (loose and crumbly) to allow water, airflow, and space for roots. At the minimum, dress lean soils with a heaping layer (several inches) of organics to dig in at planting time.
Organic matter can be completely broken down plant material, aged manure, or leaf mold. Incorporate it at least six inches deep or more among native ground if feasible. Topdress and work it with a shovel to let it rest in advance of planting, or backfill after digging and placing the new rose.
Mycorrhizae
Mycorrhizae is a beneficial fungi that form a partnership with roots and the below-ground ecosystem. In the symbiotic relationship, they carry water and nutrients to roots via a connected network of resources.
Healthy soils promote living webs like microbes and fungi. Adding mycorrhizae before or at planting may be worthwhile in promoting below-ground health. Support fungi and microbes in the future by leaving topsoil in place, avoiding deep tilling, and continuing to amend with compost in the spring.
Understanding Your Soil Type
Soil type plays a significant role in the health of all plants, especially as they provide nutrition and moisture availability. Fortunately, roses grow in a variety of conditions. Optimally, they prefer locations that are rich in organic matter and well-draining.
To irrigate efficiently, it helps to know how local ground absorbs and retains water. Typical soil types include blends of:
Clay
Clay has a slow absorption rate, slow drainage, and holds water. It needs up to three inches of water (4-5 gallons) at a time to penetrate the 16-18-inch root depth that roses require. Water permeates slowly through the clay. Clay soils may stay overly wet at shallow levels.
Loamy
This ideal soil contains organic material to aerate and retain moisture. Loams need about one and a half inches of water (2 gallons) to achieve a root depth of 18 inches.
Sandy
Sandy soils are the fastest-absorbing and fastest-draining. They dry out quickly. Sandy textures need about one and a half inches of water to infiltrate 18 inches deep but more frequently to attain regular moisture.
In poor dirt (sandy or clay), incorporate three to six inches of compost/organic matter. If your topsoil holds moisture and tends to stay wet, the matter helps with this, too. Take care not to overwater roses with supplemental irrigation (too much water or “wet feet” promotes fungal problems like root rot).
Do a Soil Test
Soil testing is a valuable tool for understanding soil composition and the state of available nutrients. A test in advance of planting lets us fully prepare the soil for roses, adding amendments to make adjustments toward spring.
Soil tests help us know what we have too much or too little of in our existing beds and how to adjust it for the best growing conditions. Tests are available through your local university extension office or as kits. Results include a complete analysis and recommendations on fertilizers and amendments to balance the minerals and nutrients.
Test results also indicate pH levels, as important as other nutrient levels for vigorous roses. If you need to balance the pH, testing indicates whether to add garden lime or sulfur. These amendments take a few months to fully incorporate and activate, so adding them in advance is optimal.
Growing in Pots
Roses grow beautifully in containers in well-draining potting mixes. Choose a pot larger than the nursery pot or root ball, but not so there’s too much excess soil volume. Surrounding soil holds water and can jeopardize young roots by causing rot or other fungal problems. Plan to increase the pot size as the roses develop.
Use a high-quality potting mix and make sure drainage holes are sufficient. Mulch with a topdress of compost in the spring for a refresh.
Treat potted roses as you would in-ground specimens in gauging when and how to plant, but keep in mind that pots lack the insulation of surrounding soil mass. Because of their above-ground siting, only a thin wall protects roots from surrounding air temperatures. In cold climates, the potting mix is susceptible to frost heaving, leading to root disturbance and damage.
Long-term, opt for a variety one to two zones hardier than your growing zone. As roses fill large containers, they’ll have the best chance of overwintering. A large pot houses more dirt volume and root mass, so it has the best chance of withstanding fluctuating conditions.
In mild climates, insulate with a thermal blanket or burlap cover during cold snaps and windy spells. In colder climates, more protection may be necessary to ward off damage.
The Role of Mulch
Maintain a two- to three-inch layer of mulch year-round to retain moisture, regulate temperature, and suppress weeds around roses. Mulch also adds nutrients as it decomposes. Apply fresh mulch after planting and water it well to keep it in place and begin moisture retention.
Mulch insulates roots and retains moisture across varying conditions. In the winter, it protects against fluctuating extremes and icy situations. Mulching helps protect roots during frost heaving when the ground naturally freezes and thaws due to temperature and moisture changes. In summer, it helps with root cooling.
Keep mulch away from stems of actively growing varieties. Leaf mulch, leaf mold, weed-free straw, compost, bark, and aged wood chips are good options. Mulch provides nutrition as it breaks down. Those all-important microorganisms get to work harnessing the nutrients for healthy growth.
