Growing rosemary successfully outdoors on the edge of zone 5

Rosemary close up Rosemary is a delightful herb best suited to warm dry climates and sandy soil. Our family has been impressed with the world of difference a little rosemary makes in our stew recipe. I know that there are many people who would like to grow rosemary but their climate is not favorable. Being on the edge of zones 5 and 6 in the mountains of West Virginia, our climate is the opposite: cold and damp with clay soil. Each winter the temperature drops below zero F once or twice. If I had known about others’ failures in attempting to grow rosemary in my kind of environment, I might not have attempted it. But since the family enjoys using rosemary so much, when I heard about a variety that was “hardy to zone 5” named ‘Madeline Hill’ I decided to give it a shot. It is important when trying something new to keep detailed records. Only then can all the factors be considered for helpful conclusions. I hope the details here will be helpful to someone.

Rosemary 5-7-08 I planted it in April ’06 in front of a small south-facing brick wall but the soil was heavy clay that had been amended with peat moss and gypsum. Because neither clay nor peat moss is recommended for Rosemary, I amended it further with sand. The wall is 7 feet from the outside wall of the house so I do not believe it receives any warmth from that source in the coldest days of winter. However, the eave of a porch roof helps keep the soil somewhat dry and that is a good thing for Rosemary.

It seemed to grow happily the first summer. The following winter I insulated the plant if the temperature threatened to go below 15 degrees. I did this by turning a crate over the plant and wrapping it thickly with burlap bags. “Thickly” means about 15 layers. Since a bag is two layers, that means a 7- or 8-bag thickness all the way around. In a 12-day period in February 2007 the temperature fell to single digits seven times, the coldest temperature being -2 degrees F. The temperature rose

above freezing only twice and the plant was covered the entire time. There were times when snow contributed to the insulation. At other times clouds, wind, and long nights seemed to render any “natural” means of warmth like the brick wall completely useless. I always uncovered the plant to provide light and circulation when the temperature was expected to stay above 15 degrees for awhile.

At the end of the winter the plant showed very little signs of any harmful effects and grew larger in 2007. It was never watered during the drought and never showed any sign of stress.

Since the crate no longer fit over the plant, the next winter I used a piece of fencing that was supported well enough to sustain the weight of burlap and snow. On December 6, 2007 the temperature was expected to fall to 15 degrees F and I almost didn’t cover the plant. But I was glad I did when the next morning the temperature on two new thermometers read 6 degrees F! During the winter of ’07 to ‘08 the cold weather came in short spurts: 2 degrees on January 4; 7 degrees on January 21; 7 degrees on February 11; and -1 on February 21. Since long term wetness is also bad for rosemary, I would keep a piece of burlap over the plant during prolonged rain or snow to shed water and help keep the A dead shootleaves dry. The plant came through the winter a second time with only a  few of the outer shoots killed. This could have been due to the dog making her bed in the burlap too. Rosemary flowers It put out a few flowers for the first time and seems to be making some seeds. I do not know what the pollination requirements are for rosemary, but if it makes any viable seed I’ll attempt to Rosemary seed capsuleplant it and see what we get.

Perhaps it would be simpler just to bring the plant indoors for the winter. But it is important to properly “harden off” the plant before putting outdoors in the spring. The year I tried that, I lost all the rosemary plants that I had brought inside after planting them out in the spring. They were “normal” rosemary plants from seed. I really don’t know if the measures I have taken to protect the hardy plant are really required. Ideally, the plant should be able to remain outdoors all year with no protection from winter cold. But I do not plan to experiment with that until I have enough plants that I could afford to lose some. If the Lord is willing there will be an update next year.

9 Comments

  1. Michael May 14, 2008 at 5:31 am #

    I still do not know exactly how hardy ‘Madeline Hill’ is. I know that regular rosemary is probably only hardy to 10 degrees F. or -15 degrees C, but I thought I had read somewhere that ‘Madeline Hill’ was hardy to -15 degrees F. If anyone knows for sure I would greatly appreciate the information. I know a few degrees below zero F is not very cold compared to what is normal for many people, but we are speaking in terms of rosemary here.
    By the way, I ended up purchasing some cheap ordinary rosemary seed and had almost all of it grow successfully by planting it in a very sandy mix and allowing the surface to dry out completely between watering.

  2. Esther May 16, 2008 at 5:19 am #

    It is a great feeling to be able to go out and pick little leaves to put in the dinner we’re making right then! We pick a lot at once and let it dry sometimes too which comes in handy.

  3. Donald May 17, 2008 at 11:57 pm #

    Great job Michael. I’ll echo what you said about a little bit of Rosemary going a long way and I pray the seeds turn out well. “He that gathereth by labor shall increase” (Proverbs 15). I’ll look forward to next year’s report too.

  4. James May 18, 2008 at 8:14 am #

    I didn’t realize you did so much to keep the plants alive! It reminds of God’s care for us; there is no way we can be hardy enough to abide the trials of this world without the care of the Great Gardener.

  5. Michael July 18, 2008 at 1:31 pm #

    That’s right, James. I’m sure glad that the other plants around here don’t take so much attention. I’m even more glad that God is not limited in the amount of attention He can give to each of us! I’m quite sure that I need a LOT more attention from God than the rosemary needs from me!

  6. Kathy March 28, 2012 at 1:02 pm #

    Really enjoyed your story…I live in Suffolk Va,And am trying to grow Rosemary myself…I only have 1 south side window and I do Kinda want to put out side but was worried about the coldness..Its kinda lookin yellow so I think Maybe watering to much??Dont know…I know it has nats all the time thats why I dont put it out and bring it in…In,Out,In,Out…Ive tryed sand for the nats…Dont know…Well anyway Thank you for your story and God Bless!!,Kathy

  7. Sally Hill February 3, 2014 at 1:23 am #

    Thank you for sharing. I live in Utah also on the edge of 5b and 6a, and we have clay soil. I grew some rosemary last year but it did not survive my husband’s rearranging in the garden. I found your story while thinking about next year’s garden. Thanks for sharing what you have learned.

  8. Belinda February 10, 2014 at 2:30 pm #

    I live in eastern panhandle of WV. I planted a rosemary of unknown variety against the west side of a mobile homes underskirting. No special soil amendments made. It survived without cover of any kind several years until home was left unoccupied one winter. I suspect the unending problem of “critters” digging their way under the home and damaging ductwork allowed heat to escape underneath.As I have never been able tp keep one alive through winter indoors,I am going to try your vatiety in a few different situations outdoors starting in May. Wish me luck!

Trackbacks/Pingbacks

  1. StaddonFamily.com » Blog Archive » Rosemary Update - February 6, 2012

    […] has already been four years since I first wrote about growing rosemary outdoors up here in the mountains! I still do not know if anyone else grows rosemary outdoors year-round in north-central  West […]

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