I am going to take out this rosemary this spring when Jeronimo comes.
It's very healthy but getting misshapen from being pruned for too tight a space and being sited up against the wall.
I'd actually like to ask Jeronimo to transplant it to the new garden by the fence. I had originally planned upright flowering perennials there -- a salvia, an agastache, a Rocky Mountain penstemon and a dwarf goldenrod.
All lovely, and I even ordered the plants before having to cancel everything with my foot injury. Would the visual weight of the rosemary be better?
But of course the new space in front of the fence is barely wider than where the rosemary is crammed now.
I had A.I. show me what it could look like there. I think it's too much and would create the same problem in this strip.
It's evergreen, and a nice looking evergreen in winter, giving me something to look at against the fence from inside the house. The perennials would be a complete nothing in winter, dormant at ground level. But I think not. I'll ask Jeronimo to remove the rosemary and discard it, not transplant it.
I'm totally confused about how big rosemary 'Arp' was supposed to get. I didn't think it would be this big in the gravel strip by the house wall.
So I asked A.I. about that -- I'm learning I can have actual conversations with ChatGPT with back and forth brainstorming and a clear explanation of the logic behind its answers.
In fact, here's the whole thing, starting with my conversational request for advice!
> Me (I attached a photo of my rosemary):
What is the mature size of rosemary 'Arp"? Nursery sites selling 'Arp' are all over the place, some say 5 feet wide, some say 2 feet wide but 6 feet tall. Some say 3 feet tall and 4 feet wide. What is your best advice on the eventual size growing in Santa Fe conditions in gravel against a sunny stucco house wall? Here is a picture of mine in a too small space. What do you think? I know I need to move it but how big will it get?
> The response:
Great question—and your photo helps a lot.
Short answer:
In Santa Fe conditions (high desert, full sun, reflected heat from stucco, gravel mulch), rosemary ‘Arp’ will most realistically mature to about:
- 3–4 feet tall
- 3–5 feet wide
…but the width is what usually surprises people.
Why nursery sizes are all over the place
You’re seeing conflicting info because ‘Arp’ is:
- Climate-responsive
In milder, more humid climates it can stretch taller (even 5–6 ft). - Cold-hardy but compact in stress
In colder, drier climates like Santa Fe, winter dieback and low humidity keep it denser and broader rather than tall and lanky. - Strongly influenced by pruning
Light trimming = fuller, wider shrub.
What yours is telling us
Looking at your plant:
- It’s already vigorous and upright
- Growing in a heat-reflective microclimate (stucco wall + stone path)
- Has room to expand outward toward the path
👉 That combination typically produces a broad, mounding shrub that leans outward, not a narrow upright column.
What to expect in your exact spot
Given your setup:
- Warm wall = faster growth
- Gravel = excellent drainage (rosemary loves this)
- Sun exposure = maximum size potential
Realistic outcome:
- Height: ~3–4 ft (maybe a bit more in a mild winter cycle)
- Width: 4–5 ft, possibly wider than tall
And importantly:
It will likely encroach heavily onto that flagstone path within 1–2 growing seasons.
Do you need to move it?
Honestly—yes, and sooner is easier than later.
Right now it’s already:
- Too close to the wall for airflow
- Positioned where its natural shape will spill into the walkway
If you leave it:
- You’ll be forced into constant pruning (which it tolerates, but it ruins the natural form)
- The interior may get woody and sparse on the wall side
Better placement guidelines
If you relocate it, give it:
- At least 3 feet from walls
- 4–5 feet of lateral space
- Full sun (what you already have is perfect)
- Same gravelly drainage
If you don’t move it
You can manage it, but you’ll need to:
- Lightly shear 2–3 times a year (never cut into old woody stems)
- Keep it off the path early before it hardens outward
- Accept a somewhat flattened, one-sided shrub
Bottom line
Your plant is healthy and happy—and that’s exactly why it’s a problem in that spot.
👉 In Santa Fe, think “wide shrub first, tall second.”
👉 Plan for ~4 feet wide minimum, likely more than the space allows.
If you want, I can suggest a replacement plant for that exact narrow space (something with similar Southwest character but a tighter footprint).
Okay, wow - that was good information, clearly laid out, and presented in a reasonable way. (I did have it suggest replacements, but didn't like the suggestions.)
