This Copernicia is absolutely healthy but it seem like needing an eternity to put on some cm in height. What are possible reasons for it? Too little water (because of slopy landscape and/or competition with an adjacent Guava shrub), too cold in winter, to poor soil all together or what else? By all means it is healthy has 4 spears in different stages of developing.

Your palm looks healthy to me . Some palms are just very slow and we just have to wait for them to grow. I don’t know anything about the particular palm you have , but I have a few palms that are very slow . I try to enjoy them as little palms , knowing I will probably never see them as mature specimens. Harry

2 hours ago, Phoenikakias said:

This Copernicia is absolutely healthy but it seem like needing an eternity to put on some cm in height. What are possible reasons for it? Too little water (because of slopy landscape and/or competition with an adjacent Guava shrub), too cold in winter, to poor soil all together or what else? By all means it is healthy has 4 spears in different stages of developing.

Konstantinos, as you said, the palm tree is not diseased. I see a plant in excellent health (let's hope the owner is in excellent health too 😁).

I'd leave it alone, it looks fine. Growth rate has to do with several factors including sunlight, these want that intense sunlight. The palms also like water but the best watering frequency will have to do with your soil and how it drains. If you must, you can use a surfactant to try and loosen the soil up(SDS or alternately the trade name SLS) but just watering more may just suffocate roots if your soil is of a limited drainage. Sodium dodecyl sulfate(SDS) or alternately sodium laurel sulfate(SLS) are potent surfactants.

Sodium dodecyl sulfate (SDS), also known as sodium lauryl sulfate, is a strong anionic surfactant that lowers water surface tension and helps water penetrate tight spaces. While it can wet hydrophobic or oil-contaminated ground and aid in soil washing remediation, using pure industrial detergent on garden or landscape soil is generally discouraged because it can disrupt microbial life and damage plant roots.

https://pmc.ncbi.nlm.nih.gov/articles/PMC11596332/

I used this in Arizona on my heavy clay soils along with a humic acid in the mix. It will help drainage and subsequent penetration of the humic acid into the soil. Humic acid makes a favorable root growing chemical environment by supporting beneficial microbe growth. If you get the concentrate, use just 1 fl oz per gallon(1/128, less than 1%) to prevent harmful effects. For me it was a one time thing and the drainage did improve. Sulfur pellets did the rest as they are slowly converted to sulfates that form gypsum with Ca in the soil, essentially correcting drainage permanently with enough sulfur. Hi calcium clay is water repellent due the Ca:Ca bonding which is broken down with the slow production of Sulfate from sulfur(go slow with sulfur, not fast with ammonium sulfate with can shift pH rapidly). If the soil is rocky, not much you can do to increase drainage. In florida I don't need any drainage correction that I cant achieve by digging and ammending so I dont use SDS at all. Use it sparingly and wisely and follow with a few humic acid rinses. For some reason I remember you have rocky soil Konstantinos, so just keep doing what you are doing it looks healthy.

I have a handful of palms that while appearing healthy, simply don't grow vertically much. Like a 15 year old Ravenea glauca, that is perhaps 2 feet tall overall, throws 3 or 4 nice green leaves a year, but never gets any bigger. Like yours, I just can't figure it out. Sorry, wish I could!

I don’t grow Copernica palms, why they are just to slow, and you’re palms are just that example of how slow!