Safe sharing in view of today's pests

I am wondering if, stripped of leaves, dipped, and bagged, it is possible to guarantee 100% clean material when sharing germplasm.

I currently operate under the assumption that I could have chili thrips.

I am no spray, and rarely see signs of such, but in October, I have noticed some stunted growth on a plant or two the past few years. I know they abound in Eastern Texas, and I did ignorantly buy some shrubs on clearance when I passed through Houston some years ago.

It seems possible that in my no-spray yard, predators might keep then in check, and that, combined with the fact that I allow my plants to go dormant in the hottest months, might account for the mild case.

I tend to presume that resistance to pesticides would be pretty minimal in my no-spray garden – though if the pests originated from the nursery trade, that could be a risky assumption.

I am wondering if I can ever in clear conscience, after stripping leaves and treating (perhaps with spinosad and some secondary systemic – I had though imidacloprid, though I’m reading mixed info) and then bagging a soil-less plant, offer to share material. (I would ask anybody to please disbud plants for a couples months too, I suppose. I don’t want to poison any native bees.)

Do you suppose one could truly guarantee clean material that way? And would it ever, under any conditions, be safe to share pollen?

FWIW I know my county also has RRD. I am assuming as long as I have found no signs of such within miles of my yard, I can share in clear conscience?

(And I assume that sterilized seed is safe.)


There are several nurseries that will not ship to me, because I live in one of the only RDD absent areas. This even includes Amazon shipping.

In my experience, pollen is the easiest, cheapest, and quickest way to share. It just requires extra planning. It is fun too. Kim sent me pollen one year and it became a game of “What should I do with this?”. It was fun lol.

With the risk of thrips, pollen worries me a little more than heavily treated plants. I don’t know how one sterilizes such.

The RRD in my county worries me. I don’t know how I would ever be able to introduce a seedling, for instance. I know a lot of folks still share material without concern for such. As I say, I have found no signs of such near me (and I probably make a lot of people uncomfortable inspecting their landscaping) but I assume it is a matter of time.

It occurs to me… Would drying and freezing clean pollen kill anything that might be on such?

You could ask David. I am not quite sure what the temperature range would be required to “cleanse” without destroying pollen.

From a biology perspective, freeze drying is a great way to preserve microorganisms, I imagine that freeze drying wouldn’t be a very effective way of eliminating plant pathogens.

The plant pathogens I am concerned about is a possibility of Chili Thrips. With the exception of one older (body bag) rose I once had which I suspected had RMV and which I never used, I have no microorganisms of concern, and would never share such if I suspected I did.

All I could suggest for CT’s would be a drench/soak in Spinosad and Imidacloprid. It’s what I would require to allow anything from an area with CT’s into my garden. We don’t have them and with all the vegetables, fruits and cut flowers grown here, I don’t want to be the one who brings them in.

That’s what I was planning, in addition to stripping of leaves and removal of soil, and letting the treated plant stew in a sealed bag in transit.

Ironically, I imagine that folks who share material indiscriminately (and probably already have such themselves) would panic if you notified them of your concerns and intentions to treat, and refuse plants they otherwise wouldn’t think twice of having mailed to then without any precautions, so the discussion might be moot.

But I wouldn’t want to share if I couldn’t feel absolutely sure I could not transmit anything.

There have already been many such discussions on Garden Web forums and Face Book. Far too few appear to consider such things. Japanese Beetles and root knot nematodes were the primary concern for many years. Then, RRD reared its ugly head. Now, Chilli Thrips. Ew.

Yep. And I’m in Texas. People have the God-given right to grow RRD-infected plants on they property if they want to, and NO one can do ANYTHING about it. Literally… (Meanwhile, folks in my neighborhood group today are complaining about multiple incidents of their unlocked firearms being stolen from their cars… Umm…)

The issue of insect infestation on neighboring properties isn’t anything new. Many years ago, a friend in Sherman Oaks had an extreme issue with a next door neighbor whose rear yard was INFESTED with giant white fly. The “cotton candy” from the infestation constantly blew into his back yard and all over his kitchen dining patio, which he and his wife constantly used. It was pretty much the only level area in the back yard, so of course it was utilized. He explained, he begged, he pleaded, he offered to pay for the elimination and maintenance to rid the offending infestation, but no dice. What finally worked was building a very tall, very long wooden wall between the two properties, reinforced with a large trellis which pissed the daylights out of the neighbor as it reduced their air flow and light, but nothing else worked. It eliminated the cotton candy blowing into the yard (it stuck to the neighbor’s side of the wall) and is, I presume, still there. Both my friend and the stupid neighbor are both now long gone.

That’s a great question about pollen and chili thrips… I don’t know… For the standard western flower thrips they seem to die when dried out after a bit with the dried pollen. I also freeze dried pollen until I use it just to store it better and suspect if they aren’t dead yet, that likely does them in. I’m nervous too about getting plants in. I try to inspect and isolate new plants and spray them if I am concerned about mites or insects from observing closely. Once I got a bareroot order of 3 roses and one had crown gall, so I sadly dumped all three since they were packaged together. I’m super concerned about RRD too. Thankfully I haven’t had any at this property yet. A few years ago the public rose garden in Minneapolis got bareroot roses from a supplier and three of a bed of 30 woke up with RRD symptoms. We got them tested and they were positive. Thankfully the whole bed of 30 was tossed asap when we saw the symptoms. Since then, no RRD has been found in the garden. The Twin Cities region is very concerned about jumping worms and gardeners are hesitant to dig up and share plants because of that. This is a good reminder… I’ve been daydreaming about roses a lot lately and have been ordering roses from different companies. When they come this spring I need to inspect them all closely and probably proactively spray them.

Thanks, David.
It kills me because I propagated a few things as backup before replanting some roses that had rooted through pots in their temporary locations. (I lost a surprising number of plants in my last move that did not recover from such.)

I have a few setigeras that are over 10 feet long that I would love to be able to safely offer, as well as other somewhat less ginormous plants, but I don’t want to share plants if I can’t get any guarantees of clean material – and I’m not anxious to buy ~$60 of chemicals for my no spray garden for such if I cannot guarantee safety of plants to give away…

Thanks for you thoughts.

…But I have a question: What do commercial nurseries, of which great many exist in chili-thrip-infested counties, do to prevent spread?? Or should one assume anything from the rose-belt growing regions is suspect? If they have thrips in their fields, I assume they are likely spraying and building resistance in which case it would seem a lot harder to insure clean material, particularly as they typically ship with leaves and soil. I would think that if they can claim clean material under such circumstances, I should be able to guaranteed such with the approach I was proposing…

Home Despot and Lowe’s nursery material all are tagged with notices which state they have been treated with pesticides which can be toxic to bees. There are Eastern nurseries which don’t ship west of the Mississippi because the owners refuse to handle the pesticides required to prevent the spread of Japanese Beetles. I know Malcolm Manners has to spray anything he ships from FSC with the pesticides required to prevent the spread of Chilli Thrips. When he brought me some of the French Teas at the HRF conference at The Huntington several years ago, we spoke about it and have chatted on line about it since. Those who have the pests and are “in commerce”, know they have them and follow the State Ag. Dept. regulations to prevent spread, OR ELSE. They can lose their nursery licenses. They can legally lose their ability to engage in interstate commerce. I’m sure there can be hefty fines involved when criminality can be determined. The difference is, they have officially determined protocols to prevent spread. You are proposing your own theories of what MIGHT work. There are protocols which can be discovered by accessing the particular states’ Ag Dept sites. Fun stuff.

I would want to be able to go above minimum standards, which I assume would be pretty wanting.

It sounds like there might be merit in reaching to Malcolm. I personally think it worth to establish/propose a standardised, and widely publicized protocol for folks desiring to share material. I am sure there is a gulf between what nurseries do and what the average Joe has been educated on and consequently even considers doing for interstate sharing.

Thanks, everyone for sharing you thoughts’ and insights.