Overwintering Container Plants

[DonnaMarieNJ]

I have several plants in small containers outdoors (the containers range from about 6 inches to 15 inches across) that for the last number of years I used to overwinter indoors. The plants are sage, rosemary, thyme, oregano, blueberry, raspberry, and a perennial grass, all of which were purchased young this year. In the past, I have tried to overwinter these varieties indoors and the plants struggled and sometimes died. This year I would like to leave them outdoors, if possible. There is no protection for them, so they will be exposed to freezing temps, wind, snow, etc. Should I water them regularly throughout the winter? Or maybe only once a month? Or should I move them all into the garage out of the elements where there will be no light and no watering available once the snow comes (and I can't open the garage door)? New Jersey is expecting a mild December, but I am concerned about the remaining wicked winter months.

I am afraid that the small containers will not protect the roots from the elements.

I also have a very nice celery plant in a container, as well.

Any help appreciated. Thank you!

[sdambr]

The sage and oregano should not be a problem at all. I leave mine on the deck in planters and they come back each year. I do not do any extra watering, just let nature do its thing. The rosemary and thyme did not do well in those planters, so I made a cold frame from a storm door, they made it through the winter with no problem. Prevously, I had brought them inside for the winter with no success. Never tried to put them inside garage, but that just might add the bit of needed protection.

[Gardeneer]

In hardness zones 7 and higher Rosemary, Sage, Thyme and some Oregano are perennial.
Maybe zone 6B too.
But if in doubt you can bring them inside like to garage and just keep the soil slightly moist.

[DonnaMarieNJ]

what about the blueberry and raspberry plants? They are in small six inch containers. Put them in the garage too? My garage is unheated and not attached to the house. Often, in winter, I cannot even open the door due to the ice and snow.

Thank you both for your replies.

[jillian]

I leave my rosemary and thyme outside during winter, on a bench against side of house under eave. I water occasionally and mulch heavily. Since your containers are small you might consider providing some insulation to protect the roots, a dense layer of leaves would be ideal.

[bower]

Donna Marie,
I've overwintered a lot of perennial plants in containers. As long as the containers are really well drained, and either find or make a place for them that's a little sheltered, plants like blueberry, raspberry, oregano and thyme and sage should come through the winter just fine without any kind of watering or other attention. The moisture and insulation they get from the snow is just right.
If you have very cold temperatures when there's no snow protection, that might be different. You might want to pile some insulating material around the pots - rocks, other pots of soil, water buckets if they can take a freeze - would protect the bare pots and exposed soil from the windchill and drying fx of cold. Any kind of solid windbreak is good here. Cover of remay or row cover might work too, I haven't tried. We often get thaws and then very cold days without protection, so when I have perennials overwintering in pots I put them in a part of my garden that's low and sheltered but well drained.
Even in the garage, I wouldn't water during the winter unless you find that the soil is badly dried out. Slightly moist is all they need until they are ready to break dormancy.

Rosemary and celery, bring them in. Neither will tolerate freezing with any certainty in my experience. I did have a celery outdoors that made it through winter last year because it was under constant snow cover. Promptly died when the snow melted and exposed to cold in the spring. Indoor and greenhouse celery did great! Rosemary I don't quite overwinter in the greenhouse, where it does tolerate some low temperatures to early winter, including below freezing air temps, but I don't have confidence to leave it year round. I brought it indoors in february last year when it started to look like it would die back from the prolonged cold.

Both celery and rosemary should do fine in a well lit place or a window indoors for winter.
Celery doesn't need a lot of light, so a windowledge with sun part of the day may be perfect. Needs even moisture which can be a constant chore in heated rooms. Keep feeding on a regular basis and it will grow, as long as the pot's big enough. If you want it bigger, pot it up.

Rosemary likes the soil on the dry side, so the challenge indoors is to keep it at that point where it's dry enough but not the dust bowl. My rosemary is pretty huge and sprawling in shape from being indoors in winter and trying to escape through the south window. If you're fussy about the shape, there'll be lots to prune by winter's end.

I've also wintered Thyme and Sage in the house. The thyme was a narrow leaved French variety that is marginally hardy here, and I had a much stronger plant after wintering inside. Lots of soft and lanky sprigs which I cut and used fresh - meanwhile the root system grew into the large pot and did great transplanted outdoors the year after.
Moisture issues for thyme and sage are as with rosemary. They can be drowned, they like it dry but just enough moisture.
The other challenge for Rosemary, sage and thyme indoors is if they get rootbound due to the pot being too small. Make sure the plants have some room to grow new roots. Small plant in a bigger pot has a buffer against root stress whether wetness or dry. In my experience, plants in 4-6 inch pots will need to be potted up for (or during) a winter's growth inside. If not they are better off to spend the winter dormant outdoors.

[DonnaMarieNJ]

Thank you, everyone!

Everything is still outside now, even though we had a few freeze scares (I've brought the hose in two times now). I want to wait until the last minute to make a decision. Every year I've brought them indoors and they suffer. Sometimes they didn't make it. Then someone said to leave them out. But the blueberry and raspberry plants are very small - I was nervous. We are having a warm December and I want them to soak up as much sun as possible. This will be the first time not bringing these plants indoors. A few years ago, I had a blackberry and brought it into the basement to overwinter. It didn't make it, so I'm a bit confused as to what to do. I have NO shelter in the backyard.

Thanks again for the info.

[Worth1]

New Jersey gets colder longer by far more than where I live.
But that doesn't mean it doesn't get cold.
My ground doesn't freeze at all but we get temperatures down to 10 degrees.
All of my rosemary is planted outside in the ground.
It actually does better in the winter.

My rosemary is Tuscan Blue and Hill hardy.
Not all rosemary is alike I know this for a fact.

Here is a small article on Hill Hardy.
Worth
https://www.google.com/url?sa=t&rct=...I05OzctPB0Vwog

[Gardeneer]

Agree with the point Worth mentioned. There are different varieties of rosemary. Some are more cold hardy than others. Up here rosemary grows like evergreen shrub in the landscapes. Actually they are blooming in near freezing temperatures. Similarly, sage and oregano are tolerant to temps down to teens.
BUT again, you winters might be much harsh. Then with some protection they can be over wintered.

[JLJ_]

Originally Posted by DonnaMarieNJ

I have several plants in small containers outdoors (the containers range from about 6 inches to 15 inches across) that for the last number of years I used to overwinter indoors. The plants are sage, rosemary, thyme, oregano, blueberry, raspberry, and a perennial grass, all of which were purchased young this year. In the past, I have tried to overwinter these varieties indoors and the plants struggled and sometimes died. This year I would like to leave them outdoors, if possible. There is no protection for them, so they will be exposed to freezing temps, wind, snow, etc. Should I water them regularly throughout the winter? Or maybe only once a month? Or should I move them all into the garage out of the elements where there will be no light and no watering available once the snow comes (and I can't open the garage door)? New Jersey is expecting a mild December, but I am concerned about the remaining wicked winter months.

I am afraid that the small containers will not protect the roots from the elements.

I also have a very nice celery plant in a container, as well.

Any help appreciated. Thank you!

In the garage, and in outdoor locations, one thing to consider is whether mice, voles, rats, squirrels, rats, etc. can get to them and if so, to do something to prevent that -- hardware cloth works if you can position it well.

Concerning small pots, I've had some luck protecting things inside or out by putting sphagnum peat around them -- either in larger containers or just around the smaller container. Depends upon how/where you store them, but it's something to consider as you make your plan.

I suspect that your blueberries and raspberries would like to be somewhere they could be dormant, but not freeze too badly -- perhaps in ground -- even if they remained in buried pots? -- if you have a sheltered location . . . and they both like sphagnum peat around them when they're growing.

Good luck!

[DonnaMarieNJ]

It's that time again, and I was just wondering - do I cut back the berry plants? The plants are new and young, but some are getting large.

[Nematode]

I overwinter potted comon rosemary.
Indoors, some light, 55f and moderate neglect seems to work.
Let it dry before watering then saturate it.
Almost dead every spring, then a miracle recovery.

I must say tuscan blue is special, I hope it works the same. Will know by spring.