To the beginner rosarian, the myriad of issues one can face is often daunting. Fungi, bugs, viruses, and user error routinely damage roses. The difficulty in overcoming these various dilemmas lies in both identification and the vast amounts of contradictory information available to the new rosarian. Of these pesky plant problems, spider mites are one of the most common. If you grow roses (or any of the other hundreds of plants they find delicious!), you will likely face off against these arthropods at some point. Spider mites are extraordinarily tiny bugs that can wreck extraordinary amounts of havoc. Often, they will have infested a plant before you ever know they’ve taken up residence! And left unchecked, spider mites can destroy a rose bush quickly.
One morning, as summer and warm weather sets in and your carefully cultivated rose bush is preparing to bloom, you may walk into your garden and notice something… odd. Overnight, your formerly flourishing plant has lost much of its foliage. Leaves scatter the ground, and the ones still on the plant are discolored. Between the leaf stems are what looks like fine cobwebs. Uh oh. You’ve got spider mites.
Now, don’t panic. Check the underside of some of those discolored leaves. If you squint, you can probably see some teeny tiny dots. Those are the spider mites. Spider mites aren’t spiders, by the way. They’re mites. The “spider” bit comes from those webs they produce to protect themselves. And these mites can’t swim or fly, so they are at your mercy! (You should not have mercy on them). So, what do you do with these miniscule pests? That depends on your rose garden. Do you have a few plants or many? Are they planted or in pots?
If you have a few potted plants, the easiest remedy would be to purchase a bucket large enough to submerse your plant. Fill the bucket with water, and dunk your plant in! (being careful not lose all your soil or upend the bush). Wrapping a bag around the base of your plant may help to keep everything where it should be. Leave the plant for a few minutes. You will need to repeat this process every three days for a week and half to ensure you’ve killed the mites and any eggs that may not have hatched before the last treatment.
If you have a few plants that are already in the ground, you can use a similar method. You will need a water wand that allows you the option to increase the pressure. Using the highest pressure of the wand with your water faucet wide open, spray the underside of all the leaves. You will need to repeat this process every three days for a week and a half.
If you have a large garden of planted roses, these methods may not be feasible. In that case, chemicals are another option. First, you should know a little about the nature of mites. A single mite can produce 20 eggs a day. These eggs can be mature mites within 5 days. What all this means is with any chemical you spray the mites can quickly build a tolerance to them. If you spray your roses twice and you still have live spider mites, you will need to switch to another chemical. The chemicals that can kill spider mites are: Flormite, Avid, TetraSan, Sanmite, Akari, and Sirocco. With any chemical, always read the instructions carefully and follow them. You will need to spray the underside of the leaves to ensure you kill the mites.
Once you’ve treated your bushes, you can look at the underside of the leaves. If you see any of those dots, they should not be moving.
These are the ways that we have dealt with spider mites at the nursery and does not encompass all the treatment options. Others might swear by neem oil, rosemary oil, or predatory mites. Hopefully this post will at least help you get started tackling a task that can initially seem daunting. As always, we’re happy to help with any questions you might have!
--Stacey