Hardy or hardiness refers to whether a plant can survive in a climate zone. A plant is hardy if it can survive the winter outdoors in Minnesota. See the next question for the definition of "zone".

Zone is a reference to the growing climate of a particular geographic area. Zone defines the climate in which a plant will survive the extreme hot or cold temperatures of a given season in the particular geographic area.

St. Cloud and surrounding areas are in Zone 4. Click here to view zone map.

We do not recommend leaving pottery outdoors over winter. Cast iron and fiberglass may survive without cracking, but the soil should be removed. It is not likely that glazed or plastic containers will survive outdoors over winter.

Spring-blooming bulbs should be planted in the fall when the ground temperature is 55 degrees or cooler. Just add bulb food to the planting hole and then cover it with soil and mulch. Summer-blooming bulbs can be planted in the early spring once the ground is "workable".

Referred to as "deadheading", removing spent flowers encourages continuous bloom and keeps the plants looking great all summer.

In fall, dig up the bulbs and remove the foliage. Allow them to dry for several days away from the sun, then store them in peat moss in temperatures of 45-50 degrees for the winter. Replant them in the spring.

You can keep tropicals year-round if you take them into the house once temperatures dip below 50 degrees. Once inside, place them in a highly lit area and cut back on water and fertilizer. As a precautionary note, check the plant for disease and pests, and treat accordingly, prior to bringing indoors.


Annuals have a life cycle of one growing season. Perennials, assuming the particular variety is zone hardy, will continue living and developing for numerous seasons.

In our experience, perennial gardens can be successful if cut back in either fall or spring. Some plants, like grasses, can be left standing to provide winter interest. However, if any of your plant material has a fungus or disease, the garden should be cut back in the fall and the diseased plant material should be removed.

Some varieties of perennials can be planted later in the season than others. Mid to late September is the general rule. The later in the season the perennial is planted, the more winter cover and protection that is required.

Mulch not only looks and smells great, but it also helps to prevent weeds, retain moisture, and provide winter protection for plants.

Cover your gardens with hay, leaves or pine needles after the ground is frozen - usually around mid-November. This is to prevent the ‘freeze/thaw’ cycle that can occur in winter on sunny, warm days when there is little or no snow cover.

"Rule of Thumb": Those that bloom in early spring, such as Peonies & Iris, divide in late August and September. Later bloomers are best divided in early spring so they have the entire summer to get established in their new home.

Fertilize perennials in May when they are actively growing, and again in mid-to-late July.

Slugs. They look like snails without a shell. They hide under mulch and leaves in cool, shady areas and become most active at night. To control them, apply a product such as ‘Slug-Bait’, as they are attracted to it, eat it, and die.

We do not advise people to divide our newly planted perennials for at least a couple of years. This is so they can become larger and more established first.


"Shade" annuals can generally survive the winter in "high light" areas inside the house. "Sun" annuals will need an extremely high/direct light source in order to survive. As a precautionary note, be sure to check the plant for disease and pests, and treat accordingly, prior to bringing indoors.

Annuals have a life cycle of one growing season. Perennials, assuming the particular variety is zone hardy, will continue living and developing for numerous seasons.

A primary reason annuals and perennials do not survive transplant is over-watering. Frequency of watering depends on plant variety, soil conditions, and weather. Containers and hanging baskets will require more water than plants that are planted directly in the ground. In containers, the plant may require water every day or every other day. When in the ground, we recommend that you test the soil with your finger. If the soil is dry to your knuckle, apply water. Note that as a plant grows it consumes larger amounts of water.

Annuals bloom best when they are fertilized on a regular basis. In the ground, every 2-3 weeks; in containers, every 10-14 days. Plants in containers do well with a time-release fertilizer.

Zonal geraniums are grown from the cuttings of a parent plant and have colored areas in the leaves called zoning. They have larger flowers than seed varieties and are much more "showy" in containers. Seed geraniums can have different color leaves but won't have the zoning and will have smaller flowers. They generally do well as a landscape plant.

Grandiflora petunias have larger flowers, whereas mulitflora petunias have smaller flowers but many more of them. Milliflora petunias have the smallest and most plentiful flowers of the three.

Wave petunias are almost all grown from seed. They have smaller flowers and will do well in the garden. Supertunias are grown from cuttings and usually have larger flowers. They don't spread as much as wave varieties and do very well in containers.

Shrubs & Trees

The best time to trim a tree or shrub largely depends on the variety. The trees and shrubs that bloom in spring should be trimmed after blooming is done for the season. Those that bloom in summer should be trimmed in fall or early spring. Shade trees should be trimmed while in dormancy.

One reason trees and shrubs do not survive transplantation is over-watering. Frequency of watering depends on plant variety, soil conditions, and weather. Generally, we recommend a "finger test" in the soil. Feel down into the soil; if it is dry down to your knuckle, apply water. In heavier soil, such as clay, check for dryness deeper into the soil. Check both the area associated to the root ball of the tree and the outer area. Water a plant until the soil is moist, allow the soil to dry and then re-water.

Trees and shrubs do not require heavy fertilization. We recommend that you fertilize every other year. If your trees and shrubs are in an area of your lawn that is fertilized, then no additional fertilizer is required.

The answer to this question depends on the variety. Green leaf and deciduous varieties can be planted as long as a hole can still be dug in the ground. Evergreens however, risk winter burn on the needles if planted after Labor Day. If planted after Labor Day, be sure to wrap the evergreen tree with burlap for the winter.

Tree Wraps/Guards prevent sunscald on "thin-skinned" and young trees, and protects from animal damage in winter.

Mulch not only looks and smells great, but it also helps to prevent weeds, retain moisture, and in the case of trees, it prevents damage from lawnmowers and weed whips.

Thomsens offers a 1-year guarantee on all of our trees and shrubs against any "natural causes of death." Specific directions are provided on the guarantee sheet you are given with your purchase.

About Thomsens

Yes, Thomsens does offer landscape design.  Our Staff Designer will come to your home, putting you one-on-one with her.  This puts her in the best position to see and understand the space to be designed, and work directly with you on your vision.  The fee for the Design Session is $100/hr.  After the Design Session, you will be presented with a certificate for $50 off total purchases of $400 or more.  Call or visit us to be set up with a designer.

Thomsens offers a gardening service for your home or place of business.  We will also plant trees and shrubs.  However, we do not offer full-fledged landscape installation. 

We are located in the beautiful hills of Collegeville Township on County Road 51 between St. Joseph and Avon. Click here for directions.

Our hours vary according to the time of year, but you can call us or check current hours by clicking here.

You can purchase a gift card at the garden center, over the phone (320-363-7375), or on-line by clicking here.

Our gift cards will never expire as long as we are here (just do not lose them!).

Thomsens offers delivery service for all of our products. The fee varies based on distance traveled, size of items being delivered, and time-frame in which delivery is required.  If you are able to wait up to 10 days for your delivery, allowing us to arrange delivery based on our schedule, delivery starts at $20.  If you require the item be delivered on a specific day and time, delivery ranges from $30 - $85; again depending on size/weight/distance.  Deliveries can be scheduled Monday through Saturday until 5 PM.

In order to achieve and maintain top quality standards, we have grown our own plants for over 40 years. We begin this process in our greenhouses in February to ensure plants are blooming and beautiful for spring.

Thomsens is open 7 days a week from April through October. From November through March, we are open 5 days a week. The only time Thomsens is closed is Easter, July 4th, Thanksgiving, and the week between Christmas and New Years.

Our focus quickly shifts to the next upcoming season in late summer and early fall. In order to ensure we are offering the highest quality plant material, we assess plant performance of the passing season, after which we begin crop planning for the next. Timing, quantity, greenhouse utilization and logistics all go into planning the spring growing season. This is an on-going process throughout the early winter, along with ordering and re-ordering based on variety availability. Further, the complexities of the greenhouses require an extensive amount of maintenance and improvements, the majority of which happens during the winter. All so we can be prepared to focus on serving you in the spring!