Newly Planted Sedum Angelina Is Struggling!

Question: Hi again --  We recently moved into a new construction home on the coast in Florence (Zone 9). Nearly 3 months ago, I planted over 800 Sedum Angelina as a ground cover in my front yard. Unfortunately, they are struggling.

As preparation, several inches of quality top soil was put over a beach sand base in both the front & back yards. My sod lawn in the back is gorgeous and the Japanese Maples and shrubs in in the front yard are all doing very well. However, as the photos illustrate, the Sedum are not. Within a couple weeks, they went from a vibrant lime green to a rusty copper color. Thus far, I have done nothing but modeately water these plants (no admendments or fertilizers).

I have no idea as to the cause of the problem...  wrong plant for this location, soil Ph, too much sun, insuffient/excessive water, lack of fertilizer, disease or infestation? No clue. I understand that once established, the Angelina variety requires little watering. I don't think I'm over watering. Any recommendations?

responder: Stephen Oldfield  Replied June 15, 2023, 10:29 PM EDT
response: All the publications I can find suggest that Sedum Rupestre Angelina is robust, tolerant of a wide soil pH range and once established, highly drought resistant. It is native to mountain areas in central and western Europe, and the orange coloration is typically a winter foliage in northern latitudes.   It looks like you have an automated watering system and it’s worth poking around in the soil to be sure that the plants are not being over-watered. The plant roots should be intact, and the soil should be damp below the surface but not soggy.   These plants were likely moved from ideal greenhouse conditions (lime green) to a new garden location, and they may be suffering transplant stress. The new conditions might feel as challenging as winter (yellow orange) for the moment, but they will adapt in our climate in full sun and start to form mats. Watch out for slugs but apart from that they should be pest-free.

responder: The Question Asker Replied June 16, 2023, 8:59 AM EDT
response: Hi Stephen -- Thanks much for your prompt and detailed reply. Very helpful. You confirmed my suspicion about transplant stress. Since we has several inches of top soil on a beach sand base, my recent planting of additonal "bling plants" confirms that we have good drainage throughout. Good thought to check, however. Your explanation makes perfect sense. I have two trays of 4" cups of this Sedum as backups to fill in any bare areas. They are still mostly bright lime green...  and are even sprouting some lively shoots. Same environment, but just not planted. With 800 of these little jewels now in the ground, I needed to understand this sudden and dramatic color change. Again, many thanks. Last question: I typically use an organic 10-10-10 fertilzer once in the spring and once in the fall. Will this aid the sedum growth? Should I use this fertilizer, something else, or nothing at all? Regards, Norm

responder: Stephen Oldfield  Replied June 18, 2023, 2:32 PM EDT
response: Going back to those publications, these plants thrive in mountainous areas with shallow, rocky soil.  Your high quality topsoil should provide all the nutrients they need for some time.  Adding more nutrients (particularly Nitrogen) could encourage softer growth and also enable weeds to establish.    I would hold off and keep monitoring the plants.  Look for patterns to see if they grow best in more shaded or sunnier areas, closer to the conifers or closer to the curb.  Patches that stay damp for longer after irrigation or those that dry out fastest.  You have enough environmental variation in the bed to find out what works best.

responder: The Question Asker Replied June 18, 2023, 4:46 PM EDT
response: Thanks again Stephen, Wise advice… and I will follow it. About 15 years ago, we moved from San Diego (where just about anything seemed to grow well) to Bend Oregon. Living there, I realized I needed professional guidance on several occasions. I used the services of Ask Extension four times and the recommendations were always spot on. Now that we are on the coast in Florence, this location presents its own unique challenges. Your expert direction is much appreciated. Warm regards, Norm