I wouldn't prune at all and that isn't variegation it looks like a nutrient deficiency or mix problem. Not sure which though so hopefully a pro can weigh in.

Looks like Manganese deficiency; it is often associated with high pH soils and or cool weather.

I'm no pro, but your mix looks very heavy. Many of us here use either the "gritty mix", or the 5-1-1 mix (my favorite). I have had great success with trees in those mixes and using Oscomote Plus and Foliage Pro. In the 5-1-1, I use Foliage Pro every 2-3 days and my trees are very happy and green. I would not prune either. The branches look nice. We can help if you have more questions.

So should i replant in different mix? Is that the best option? They are growing fantastically these past 3 weeks its just the deficiency of any nutrients im worried about. What's the easiest way to test my soil?

The problem with a "heavy" mix is that it is easy for many people to over water which results in water logged roots starved for oxygen, root rot and death of the tree. This may occur over more than a few weeks. Mixes like the gritty mix and the 5-1-1 do not retain as much water and make it less likely that the tree will develop root rot. The gritty mix retains the least amount of water and the tree is least likely to develop root rot. But many people find it too much of a bother to hunt down the ingredients and then put them through sieves. The 5-1-1 is easier to find the ingredients and make but retains more water. However that means you don't have to water as often as the gritty mix.

My version of Al Tapla's 5-1-1 Mix

· 5 parts pine bark mulch (remove ½” pieces through 1/2 inch screen)

(Some people use Repti Bark instead of mulch without screening)

· 1 part sphagnum peat

· 1 parts perlite (coarse, if you can get it)

· 1 Tb/gal 5-1-1 mix garden lime (measure the 5-1-1 mix)

· Controlled release fertilizer (optional)

· Moisten and wait 2 days before using

For fertilizer, use Foliage Pro 9-3-6 and add 1 Tsp./gal. Use that whenever you have to water instead of pure water. Get a cheap pH tester the kind used to test the pH of aquarium water. If your tap water is above pH 6.5, add vinegar to adjust it to about pH 6.5. You will only have to add give or take a 1 Tb/gal. So, you will be watering with a mix of vinegar and Foliage Pro every time the tree needs water.

Certainly a nutrient deficiency. johnmerr is probably correct that this is manganese deficiency, but with citrus manganese and iron (and even zinc) deficiencies are difficult to tell apart. The pH of the soil is probably high (7.5 to 8.0) although that's just a guess. Soil tests for these nutrients are difficult to interpret because plant genetics control uptake to a significant degree, so the cost of a soil test is not warranted.

Either re-pot in a different soil or lower the pH of the existing soil with a small amount of sulfur.

i just bought to Moro Blood Orange trees 3-4 yrs old and the tips - the youngest growth has turned brown and a 4 inch section of a branch is brown - thoughts? I live in southern Ma. a bit windy but sunny

Nancy

Nancy, please post a picture and tell us how you have taken care of it: what kind of fertilizer, soil, how often you water, etc.