Natalie, I think your graduate student should define what she means by “sand”. Sand may include a variety of things–such as naturally occurring organic “amendments” which will vary according to the source and location of the “sand”. If the student expects the rose to grow in silicon granules with no organic content (such “sand” rarely occurs in nature), she should say so. I can’t see what would be learned from such an experiment–except that nutrients are required for growth.
She is studying temperature affects on the root zone and needs to measure CO2 efflux.
The easiest way to control microbial contamination, control plant nutrients and control water levels is to use sand.
She also needs ‘windows’ cut into the pots to visually monitor root growth. Pictures have to be taken on a regular basis and run through a computer program (that to my understanding is already calibrated for roots growing in sand).
I will try to learn more and post more details later.
When you say no “amends” surely you do not mean no nutrients, do you? This is somewhat like growing hydroponically? Without the nutrients, there isn’t going to be much growth. I would think that rosa wichurana would grow well in sand.
This will teach me not to post something without explaining myself well!!!
I didn’t mean to add confusion about the growing specifications…I just wanted to know what roses grow well in sand.
She is currently trying to grow a few varieties for the experiment in pots full of sand, but it’s not working very well for her. She is controlling the amount of water and nutrients the plants receive. The plants just aren’t growing very much, and I was thinking that it may be that we need to get a few varieties that are known to grow well in sand.
So, thanks for the suggestions that have already come in:
R. fortuniana (Kim)
R. rugosa (Rob B)
R. nitida (Rob B) &
Louis Philippe (Charles C)
Are there any other named varieties/cultivars that are easily obtainable that you think we should use?
“Not growing much…” Seems Fortuniana would be the best bet. You know it’s a weed there with an extensive, rampant root system. If THAT won’t perform in those conditions, what on earth will? The only other rose I’d suggest would be multiflora. Both have been used with great effect there for production because of their root growth. They are easily obtainable, rampant growers with far reaching roots which should be easily photographed and documented and both should grow quite quickly in your conditions. You probably already have much of both around. Seems a no-brainer to me.
Natalie, you may want to consider using Turface rather than sand. Either the traditional size (MVP) or the fine size (quick dry). It has a pretty good cation exchange capacity and water holding is probably better than sand. We use it to grow corn in containers. Oh and the particle size differences do influence how the roots develop. Drop me an email if you need more info.
“The easiest way to control microbial contamination, control plant nutrients and control water levels is to use sand.”
What kind of control??
Many years ago there was a shift from growing florist roses in soil to soilless substrates. Inert ones such as sand were first used then perlite and pouzolane and later coco choir were prefered.
These florist roses are/were mostly grown own root. Var or species is not the key but beside oxygenation, bacterial and mycorhizal funghi are needed. Without a biologic cortege plants are as little able to assimilate nutrients as we are.
Take a look at hydroponic supplies and you will see. There are a profusion for hemp growers…
For a number of long considered incurable or orphan deseases decisive actual human medecine progress is done considering our colon flora health as indispensable to good assimilation and balanced immune system.
I suspect her problems are due to the high pH of your water combined with drowning the roots in deoxygenated water.
She might have better growth if she can keep the environmental temperature at or below 25 degrees C, adjust the water to pH 6.5 to 6.8 (a bit less for rugosas) and allow the sand to drain completely and continuously - no standing water. so pretty much constant drip irrigation.
I have a setup at work called an aquaponics system. It is a take-off of hydroponics except we have fish in a large tank and four growbeds and the water from the fish tank is constantly pumped out and into the growbeds that act like large (4 x 700L) biological filters. They are full of ordinary inert gravel and hydroponic clay beads. There is an auto-syphon attached to each bed so that the water reaches a certain height and then flushes quickly into a sump below where it is pumped back into the fish tank. The rate the water enters the growbeds is significantly slower than the rate at which it drains. We grow vegetables in the growbeds but I have been experimenting with a few things using Flower Carpet Pink cuttings. I wanted to see if they would callous and form roots in a flood-and-drain setup. They did and continued to grow well. If it doesn’t have to be sand, perlite would work just as well and avoid compaction and provide air-spaces. I think most roses would grow under these conditions.