{"id":2853,"date":"2019-11-14T00:06:21","date_gmt":"2019-11-14T08:06:21","guid":{"rendered":"https:\/\/depts.washington.edu\/hortlib\/pal\/pal-question-581\/"},"modified":"2023-08-08T14:28:19","modified_gmt":"2023-08-08T21:28:19","slug":"lack-of-flowering-on-magnolia-grandiflora","status":"publish","type":"pal","link":"https:\/\/depts.washington.edu\/hortlib\/pal\/lack-of-flowering-on-magnolia-grandiflora\/","title":{"rendered":"lack of flowering on Magnolia grandiflora"},"content":{"rendered":"

I have a<\/strong>
\nvery tall, well-established Magnolia grandiflora<\/i>. The tree is located on<\/strong>
\nthe southeast corner of the lot. Every summer it has produced large white<\/strong>
\nflowers, but last summer that there weren’t as many blooms, almost<\/strong>
\nnone. It’s left alone and watered spring through summer by a sprinkler system. I have also noticed yellowing of the leaves at the ends of the branches. Usually the leaves<\/strong>
\nhave been dark and green. I’m wondering if it is a lack of nitrogen or food of some sort.<\/strong><\/p>\n

 <\/p>\n

There are a number of reasons that plants may fail to flower, and it
\nwould be difficult to pinpoint precisely why the Magnolia made such a
\nweak show this past summer. Sometimes, cold temperatures kill off flower
\nbuds (and there were some cold snaps last winter). The tree is not
\nimmature, and it sounds as if it is not pruned improperly, so those
\npotential causes can be excluded. You also indicate that it is not
\nfertilized, so it is probably not receiving excessive nitrogen which can
\nlead to lots of leafy growth at the expense of flowers. I wonder if
\nanything else in its environment has changed: has the amount of light
\nchanged (any new construction obstructing sun?), or has anything happened
\nto the soil where it is planted? You might wait and see if flowering
\nreturns to normal this year.<\/p>\n

As for the yellowed leaves, that might be a result of winter injury
\n(desiccation) or drought stress. However, yellow leaves can also be a
\nsymptom of sunburn or lack of light, or nutrient deficiency. See the
\nlink here<\/a> to University of California, Davis’s page on Magnolia problems. Excerpt:<\/p>\n

Mineral deficiencies:
\nCertain nutrients, in relatively small amounts, are required for healthy
\nplant growth. Deficiencies can cause tip chlorosis or necrosis or cause
\nfoliage to discolor, fade, distort, or become spotted, sometimes in a
\ncharacteristic pattern that can be recognized to identify the cause.
\nFewer leaves, flowers, and fruit may be produced, and these can develop
\nlater than normal and remain undersized. More severely deficient plants
\nbecome stunted and exhibit dieback. Commercial laboratories can conduct
\nfoliage tests or soil analysis to verify deficiencies.<\/p>\n

Identification\/Solutions:<\/p>\n

Nitrogen and iron are the only nutrients in which woody landscape plants
\nare commonly deficient. Poor root growth caused by water-logged soil,
\nroot diseases, and nematodes can also cause iron deficiency symptoms.
\nFertilize only as needed and only if other problems have been eliminated
\nas the cause of poor growth. Avoid overfertilization, especially with
\nhigh-nitrogen fertilizers. Slow-release formulations of nitrogen or
\norganic fertilizers reduce some risk of overfertilization. Correcting
\ndeficiencies of minerals is tricky. Apply only the mineral found to be
\ndeficient. In some cases, soil characteristics may exacerbate
\ndeficiencies. Alkaline soil (high pH) often makes iron or manganese less
\navailable; reducing alkalinity with sulfur or organic amendments (peat
\nmoss) may be all that is needed. Some minerals such as iron, manganese,
\nand zinc are absorbed more rapidly as a foliar spray than a soil
\napplication.<\/p>\n

If the environmental causes don’t ring true with your tree’s situation,
\nyou may want to do a soil test to see if there are nutrients which need
\nto be supplemented.<\/p>\n","protected":false},"excerpt":{"rendered":"

I have a very tall, well-established Magnolia grandiflora. The tree is located on the southeast corner of the lot. Every summer it has produced large white flowers, but last summer that there weren’t as many blooms, almost none. It’s left alone and watered spring through summer by a sprinkler system. I have also noticed yellowing of the leaves at the ends of the branches. Usually the leaves have been dark and green. I’m wondering if it is a lack of…<\/p>\n

Continue reading lack of flowering on Magnolia grandiflora<\/span><\/a><\/div>\n","protected":false},"author":4,"featured_media":0,"menu_order":0,"template":"","keyword":[746,205],"class_list":["post-2853","pal","type-pal","status-publish","hentry","keyword-magnolia-grandiflora","keyword-trees-diseases-and-pests"],"acf":[],"_links":{"self":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/pal\/2853"}],"collection":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/pal"}],"about":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/types\/pal"}],"author":[{"embeddable":true,"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/users\/4"}],"wp:attachment":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/media?parent=2853"}],"wp:term":[{"taxonomy":"keyword","embeddable":true,"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/keyword?post=2853"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}