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our 'black tulip' magnolia flowered a but but has since shrivelled with the leaves dying. Any ideas what's wrong and how to revive it?
Hello @philipmkeane
Thank you for sharing your question about your "black tulip" magnolia. Can you please provide us with a little bit of history in regards to the lead up of the downturn in the health of your plant?
- How often were you watering the magnolia?
- Did you apply any fertilizer or chemical booster to the plant recently?
- Were you spraying any form of weedkiller or chemical spray around the plant's vicinity?
- Is the soil currently damp?
- Did you happen to experience any sudden temperature or weather changes?
- Is this the first time that it has happened and are any other plants affected?
- What is your soil type and general location.
While we are waiting for your answers, I suggest having a look at these guides - How to diagnose a sick plant by @Noelle and How to treat Magnolia with dried leaves? by @philipmkeane.
Any extra information you can provide would be very much appreciated.
If you have any other questions we can help with, please let us know.
Eric
Hello @philipmkeane
Thank you so much for that extra information. From your photo and the information you’ve shared, it sounds like your Black Tulip magnolia is experiencing stress rather than a disease outbreak. There are a few likely causes, and fortunately, most are reversible with the right care.
First, your watering schedule combined with recent rainfall may be leading to overly wet soil. Magnolias dislike waterlogged roots, particularly in clay-heavy subsoils like those in the Adelaide Hills. Even though the top layer feels only “a little damp,” the deeper clay can stay saturated, depriving roots of oxygen and causing leaf wilt and dieback. Try probing the soil 10–15 cm deep; if it feels sticky or heavy, reduce watering frequency to once a week, allowing the soil to dry slightly between sessions.
Second, as your magnolia is newly planted, it’s still establishing its root system and is very sensitive to sudden changes in moisture or temperature. Even a short dry spell followed by heavy rain can cause stress symptoms that look like this. Mulching with a 5 cm layer of organic material (such as pine bark) around the base but not touching the trunk will help moderate moisture and temperature fluctuations.
Third, consider the fertilizer application. If a chemical fertilizer was used 1–2 months ago, it could have contributed to mild root burn, especially if followed by heavy rain that carried salts into the root zone. In that case, a deep soak with plain water to flush the soil helps. Avoid fertilizing again until you see strong new growth. When you do, use a slow-release fertilizer formulated for acid-loving plants.
Lastly, check for any physical damage or pests at the base or lower branches. Magnolias are prone to sunburn or borer attack when stressed, and the symptoms can mimic water stress. If bark looks split or damaged, apply a tree guard or shade cloth on the west-facing side for protection.
To help with monitoring the soils moisture content I propose investing in a Brunnings 3 in 1 Soil Meter. My best advice is to be very careful of the probes and avoid bowing or bending them. Do not use excessive force when pushing it into the soil.
If you need further assistance, please let us know.
Eric
