Starting Bare Roots In Containers

By Robert B. Martin, Jr.

Pasadena, California

January is the time to start bare root roses in Southern California and the nurseries teem with information on how they should be planted in the ground.  But there is a better way to start a bare root rose - in a container.  Most people are not even aware that this is an option but it is and it is the way I start all of my bare root roses.  So let me explain why in case you'd like to do the same.

Advantages

The advantages to starting bare root roses in containers are many and they include the following:

Less Commitment

Roses are particularly susceptible to differences in micro climates which means simply that a rose may do better in one place in your yard than in another.  Also it is difficult to tell in advance exactly how tall the rose will grow in your yard and whether the color of its blooms will be harmonious with its neighbors.  Planting roses in containers provides you the opportunity for you to evaluate it in a particularly exposure and then to easily move it to another if that seems useful.  In the process you can learn where it will perform best before committing it to the ground.  You might also learn that it is simply a crummy rose.  By starting the rose in a container it becomes a much easier matter to send it to a place that it deserves which may very well be your dumpster.

Less Competition

Roses do not like competition from other plants. This is because they are heavy feeders and other plants, including neighboring roses, often deprive them of nutrients and room for their roots to grow. Roses also do not like shade and planting a new rose between established roses often results in it being deprived of sunlight as its taller and more established neighbors leaf out.  Planting a new bare root rose in the ground in an established rose bed is like trying to start a new tree in a forest - it is tough for it to ever catch up to its neighbors.   However by planting a rose in a container the nutrients can be delivered to the rose alone, its roots can freely develop and it can be placed so that it does not have to compete with its big brothers for sunlight.

Less Soil Problems

The rose literature has for years spoken of a problem called "soil sickness". New roses generally do poorly when they are planted in a spot where roses have grown before and the soil is usually the suspect at which fingers are pointed.  But there is little agreement with respect to the reason for the problem; some blame nutrient loss, others nematodes, and others fungal growth in the ground.  (I personally believe that the problem has more to do with the failure to remove all of the old rose roots which have displaced the soil and may either harbor fungal infections).  Be that as it may it is clear that planting in containers provides the opportunity to use a fresh clean planting medium which will assure the new rose that it will not have to deal with soil problems while becoming established.

It is also clear that light well aerated soil is the best environment in which to encourage root development.  The prime and initial directive for a bare root rose is to develop a good root system.  By planting a bare root rose in a container you can use a light planting medium that the roots can easily invade.  This is much better than forcing the rose to set its roots in the heavy clay soil that is common to Southern California.

Also when roses are planted in a hole dug in heavy soil the result will usually be what nursery people call the "bath tub" effect.  Water applied to such roses does not drain well into the surrounding soil thus leaving the rose in a bath tub full of water.  The roots of a rose need oxygen to breathe or they will literally drown.  This is why good drainage is so important to root development and it is easy to get good drainage in a container.

Easier Care

Another advantage to starting roses in containers is that it is easier to care for them.  Nutrients and water can be applied more exactly and there is easier access to the entire bush for spraying.  The container lifts the rose off the ground which permits a higher access and the ability to easily turn the rose around.  In particularly access to the undersides of the leaves, which on young plants would otherwise be too close to the ground, is improved.

How to Do It

The technique of container planting is relatively simple and can be best understood by keeping in mind the advantages described above. Here's how...

Container Selection

The key to container selection is to provide the rose with adequate but not excessive room for root development.  A rose sets its root system well before putting  on much top growth; it is in fact the root system that supports the top growth. Yet top growth should be encouraged as well so that you will have some idea at an early date of what the rose will look like.  For large size roses the preferred starting container is a 5 gallon plastic container.  For miniatures the preferred size is a one gallon plastic container.  Such containers are available for a modest price at most local nurseries; if you are a good customer some nurseries will give you their used containers.

Planting Medium

The preferred planting medium for starting roses in containers is light, loose and sterile.  I make my own which is simply a mixture of one part potting mix and one part #2 perlite. I prefer LGM Potting Soil which I buy in quantity at Bellefontaine Nursery in Pasadena.  I like it because it has plenty of fine peat and organic matter.  Also it does not have vermiculite in it.  Vermiculite is a clay and adding clay to my soil is like taking sand to the beach. There are also other planting mixes, including various soilless mixes that are commercially available, so look around and find something you like.  Do not use soil or compost in the planting medium because it can harbor harmful fungal disease or bacteria.

Rose Preparation

The bare root rose should be prepared for planting in much the same manner as if it were to be planted in the ground.  Soak the rose up to its neck for 24-48 hours in a trash can or large bucket full of water.  I generally add SuperThrive, a handful of aspirins and some amino acid tablets, although I cannot recall why I do the latter.  Whether these additions really work or not is not certain but I think it does and it can do no harm.

Prior to potting up the rose the roots should be examined and obvious broken ones removed.  Clip off the end of a few of the fatter ones to promote lateral growth and shorten any that are much too long to fit conveniently in the container. (In this regard you should err on the side of leaving the roots as they are; if you are uncertain about the size leave them alone).

Container Preparation

I used to put down a layer of redwood chips or pottery at the bottom of the container in order to prevent the planting mix from running out the holes.  I no longer do this because pottery can plug up the holes and the chips tend to rot at the bottom.  So, instead I put a layer of pure potting mix, or perhaps a heavier planting mix, at the bottom and tamp it down.  You should then add a layer of the planting medium and poke a depression in it with your finger. Fill the depression with superphosphate (bone meal is too alkaline and also creates a fine cloud I do not like to breathe). II actually use an old metal soup ladle to poke the depression and add the superphosphate.  Use about 1/4 cup of the superphosphate with a large rose and about 1 Tablespoon with a miniature. The objective here is to keep the superphosphate in a lump or pile.  (There is a very good reason for this - phosphates are important to root development but tend to bind to adjoining soil and become unavailable to the roots).  Then you should put down another layer of planting mix.  Place the rose in the container and arrange the roots in a circle and then fill the container with the planting mix holding the rose firmly at the desired level.  Shake the container and poke the mix with your gloved fingers to settle the mix; then add water to settle it further.  After the water has drained refill any obvious holes with planting mix and then pour on a gallon or so of the solution used to soak the rose.

Later....

Having committed to planting the rose in the container you must plan to keep it in the container until the roots have totally involved the medium.  When this occurs the rose can be easily removed from the container with the root ball intact.  However if you remove the rose prematurely you will be unable to maintain the root ball and the soil will fall off damaging the fibrous root system which initially develops.  As a general rule a rose planted in a container in January should not be removed from the container until early June.  At this time it can be easily planted in the ground. It can also be left in the pot for Fall planting or it could be transplanted to a larger pot.  This gives you all the time you could need to evaluate the rose and it is this flexibility that makes starting roses in containers a very useful idea.

Reprinted from the January 1999 issue of "The Rose Parade," bulletin of the Los Angeles Rose Society.