Junipers and Fertilizer times and Nitrogen

Question

Reading around the web, many say the exact opposite of another 'expert'.

Specifically pertaining to Junipers, I'm reading don't use nitrogen or use high fertilizers high in nitrogen.

When is the best time to fertilize and what fertilizer do you recommend?

• They are all potted junipers

• I have 7 Junipers, 20l x3, and the rest in small pots.

• One, potted in a cascade pot is almost completely brown

• Another has brown at tips

  • The youngest 2 are suffering the most

  • They were all repotted 14 months ago and have been doing well until a few months ago.

Soil used. 3 parts: A general potting mix strained to remove fine particles and sand. Organic including pine bark left 1 part Vermaculite and Leca add Bone meal add Seaweed add multicote slow release

weather here is not the best. - Strong winds. average 20km gusts 30km - Our summers are hot 28c + - we have moved into autumn and it averages 24c

They are positioned outside on benches. They receive partial to full sun.

Focusing on the two unhealthy junipers.

I forget the exact species, but its blue crawling variety. The second is marketed here as Gold Coast

Watering. I cant explain, but I sense when it needs it, the way the tree and soil is looking on the surface. Since the wind and sun dry the pots out fairly quickly, it tends to be every day when at its worst or 4 days when its calmer.

The scales seem to thin when under watered (This is probably not factual) and droop when rounded, when it gets too much. Once again, not science. Its worked for years and they are healthy trees except for the two.

Thee crawler is potted in a cascade but is completely brown except for odd tips. I worry about the cascade pots for air pockets so I tap the pot and water it well often. I have tried a number of things, including liquid fertilizer 6 months ago, but nothing is perking this tree up. Should I repot? Would another bout of liquid fertilizer rich in nitrogen help this tree? Should I pit it in shade..

the other has brown tips (the opposite) to the crawler. Its potted in a forest with Natasja Ficus. Its a shallow pot but the roots have lots of horizontal space. All the other trees are doing well in the same planting.

Answer 1

I've been checking information for conifer growing where you are - if your Junipers are growing in open ground, there is no recommendation to give them fertiliser on a regular basis. There is a recommendation that the soil they're planted in should be improved prior to planting by incorporating bone meal/fish blood and bone and good humus rich material such as composted animal manure or your own good garden compost, followed by mulching, preferably annually, with an organic mulch (composted materials, composted animal manure,whatever you can readily get there). The main purpose for mulching is to help with water retention in the soil, but it has the useful side effect of enabling the plant to access its own nutrients as and when it needs them. Water seems to be the most critical requirement; there's a statement here http://www.egardens.co.za/landscaping-library/conifers/landscaping-with-conifers which states that conifers will grow on quite poor soils, but obviously do better and look better if you plant in fertile soil.

If you didn't enrich the soil beforehand, then make sure you apply humus rich mulch on a regular basis, preferably onto soil that is damp, not bone dry, but don't let any mulch sit against the trunks or woody bases of the plants. The only proviso I would make is if you choose to use bark chips, in which case, I'd lightly scatter a handful or two of a basic granular fertiliser beneath it, something with an NPK of 7-7-7 or similar (in the UK, that would be Growmore) and that only in spring, once.

Answer 2

All domesticated plants, crops and garden need fertilizer. Pure and simple. I wouldn't use high nitrogen for flowers or fruiting crops but junipers would be fine. Are these junipers MATURE? Have they ever been fertilized? Fertilizer are chemicals necessary for plants to make their own food. We strip these chemicals away when we build and it is up to us to manage the soil, improve the soil with organic matter, preferably decomposed so it is up to us to replace necessary tilth, food for soil organisms and chemicals that plants have to have. Dunno where this stuff that fertilizer is bad comes from but my goodness. Stable ecosystems all the chemicals or FERTILIZER plants need are caught up in the living foliage and organisms. Being released slowly as plant parts fall off and die and the soil organisms die. No way could one grow a desired plant in a stable ecosystem much less a non ecosystem without adding chemicals and decomposed organic matter to feed the soil organisms that work with plant roots to up take the chemicals plants have to have for photosynthesis...to make their OWN food.

Mature shrubs should be fertilized once per year using a slow release fertilizer; good old NPK plus micronutrients. I'd use OSMOCOTE 14-14-14. Simple and sure. Once per year should be plenty. What are you using for mulch? What kind of soil? Have you ever had a soil test? If not go get one. It will tell you what your soil has in abundance and what your soil is lacking. That is the best way to be responsible and to not take chances with fertilizer or any 'additives'. Over fertilization is a QUICK and SURE kill.

Where the heck is this 'no fertilizer' campaign coming from? Chemicals are chemicals no matter 'synthetic' or 'organic'. All the same. Free or very inexpensive soil tests can be done through your Cooperative Extension Service of your closest University. Pesticides are different. Fertilizer in no way is in the same category; herbicide, fungicide, pesticide...these kill certain forms of life that essentially got out of control because someone used a pesticide and killed off all beneficials that controlled a few organisms or their manual techniques of watering or pruning caused a problem and pesticides are a Band Aid. Fertilizer is critical chemistry plants have to have to survive. Too little is bad and a little too much is even worse. We humans strip away topsoils with some of these necessary chemicals and thus WE have to replace them. Or make your yard a parking lot of asphalt.